cahya/wikipedia-simple-en huggingface dataset:
Snow

Snow is a form of ice. Snow forms when water in the atmosphere becomes frozen. Snow comes in all different shapes and sizes.

At the freezing point of water (0° Celsius, 32° Fahrenheit), snow melts and becomes liquid water. Sometimes, the snow will melt very fast and become water vapor. This is called sublimation. The opposite, where water vapor becomes snow, is called deposition.

Snow is used for some winter sport activities like skiing and sledding. Sometimes people make artificial snow so they can ski. People also commonly build things out of snow for fun.

Snow can also be dangerous, as it can lower visibility and make driving very difficult. When it snows, the snow will melt a little during the daytime and freeze again at night. This makes ice which can make driving conditions very treacherous. Snow plows are used to remove snow from roads to make driving easier and safer. Also, sand or salt may be added to the road to help tires grip the road. When salt is mixed with snow, the snow will melt more easily. This is because salt water has a lower melting point than fresh water (water without salt).

A blizzard is a dangerous type of a snowstorm. A blizzard produces strong winds that keep the snow in the air, thus reducing visibility. Sometimes it produce thunder snow, which is snow with lightning and thunder.

References

Snow
Snow
President

A president is the leader of a country or a company or other group. A president is usually elected by the people in that group. Voting is one way to elect a president.

Electing a President 
The President of the United States is elected by the electoral college. Some other countries choose a president this way. In some, the Parliament does it. Some countries have direct elections to choose a president. Many countries have a monarch instead of a president and some have neither.

Companies have presidents. They are elected by the people who own part of the company. In some companies, the people who are workers for the company elect (vote for) their company president.

Power of a President 
The president of a country is not the same thing as a prime minister. A prime minister is part of a parliament, but a president is not. In some countries, (such as the United States or France), the president has more power and responsibility than anyone else.  Such a president is often called the nation's chief executive.  As chief executive, the president must take an active role in all phases of government.  In other countries (such as India, Israel or the Republic of Ireland), to be president is more of an honor or a symbol, and the position has no real power.  This kind of president is often called "head of state". 

Most countries that have a King or Queen as their monarch have no president. 

The American President is restricted by the written United States Constitution, which was written to make sure that the American executive never became as powerful as in the British system.  The British Prime Minister is part of both the Legislature and Executive, whereas the American President is the head of the Executive. The American governmental system shows a clear separation of powers unlike the British system.
         
 All the president's ministerial appointments have to be vetted by Congress (Parliament) and Congress may have an opposition majority.
 The president does not have the ability to introduce and influence legislation in the same way as the British prime minister.
 Congress has much greater control over the budget and foreign policy than the British Parliament.
 There are broad areas of American life, such as education, crime and punishment, over which the president has virtually no influence at all.
 The president even has very limited control over the economy.

So despite having a large nuclear arsenal, the American president can not carry out policy and introduce legislation as freely as the British prime minister.

Related pages
 Head of state
 Monarch

Other websites 
 Presidents of the United States

 
Titles
List of colors

This is a list of all the colours.

Related pages 
 Lime

Lists
Promise

When a person agrees to do something or to not do something, that person is making a promise. A promise can be made   (by saying it), or it can be written down as a contract. Breaking a promise, or not keeping it, is often just bad manners, but it can sometimes be illegal, such as when a contract is not kept.

A vow is a special promise.  It is mostly used in a religious sense or in ceremonies such as marriages when the couple who are being married make their "marriage vows", promising to be faithful to one another.

An oath is a promise in the legal sense.  When someone has to give evidence in a court of law they "swear an oath".  This means that they promise they will tell the truth.

Ethics
Law
Water cycle

The water cycle (or hydrological cycle) is the cycle that water goes through on Earth.

Water is essential for life as we know it. It is present throughout the Solar System, and was part of the Earth from its formation. The source of the water was the same as the source of the Earth's rock : the cloud particles which condensed in the origin of the solar system.

Processes
This is the process that water starts and ends in the water cycle.
 The cycle starts when water on the surface of the Earth evaporates. Evaporation means the sun heats the water which turns into a gas.
 Then, water collects as water vapour in the sky.  This makes clouds.
 Next, the water in the clouds gets cold. This makes it become liquid again. This process is called condensation.
 Then, the water falls from the sky as rain, snow, sleet or hail. This is called precipitation.
 The water sinks into the surface and also collects into lakes, oceans, or aquifers. It evaporates again and continues the cycle.

Humans activities that affect the water cycle
Human activities that change the water cycle include:
 Agriculture
 Industry
 Building dams
 Deforestation
 Removing groundwater from wells
 Water abstraction from rivers

Related pages 
 Carbon cycle
 Rock cycle
 Drought
 Ecohydrology
 Flood
 Rain
 Bioprecipitation

References 

cycle
Weather
Earth sciences
Contract

A contract is an agreement or promise that the law can enforce. The law will enforce some agreements but not others. For example, in most places, if a parent promises to take a child to get ice cream, the law will not enforce that promise as a legal contract.

The legal rules about which promises are enforced by the law can be different in different places (or jurisdictions), but a contract is usually enforced only if it is made by people or groups who want it to be enforced and who know what they are doing.

Sometimes, a contract is written down and signed by the people agreeing to it, but it does not always need to be. People usually sign a contract when something important or costly is being done. For example, when people take a job, they will sometimes sign a contract with their employers. The contract will show what the person must do as part of his job, how much they will be paid, and so on. The person and the employer will sign the contract, and it will become a legal promise.

If someone breaks a contract, another person might sue him or her. In a lawsuit about a contract, the court will look at the contract, listen to what the people who made the contract say about it, and then make a decision about what the contract means.

Related pages
 Law 
 Oath

Law
Documents
Kolkata

Kolkata (spelled Calcutta before 1 January 2001) is the capital city of the Indian state of West Bengal. It is the second largest city in India after Mumbai. It is on the east bank of the River Hooghly. When it is called Calcutta, it includes the suburbs. This makes it the third largest city of India. This also makes it the world's 8th largest metropolitan area as defined by the United Nations. Kolkata served as the capital of India during the British Raj until 1911. Kolkata was once the center of industry and education. However, it has witnessed political violence and economic problems since 1954. Since 2000, Kolkata has grown due to economic growth. Like other metropolitan cities in India, Kolkata struggles with poverty, pollution and traffic congestion.

History 

The discovery of the nearby Chandraketugarh, an archaeological site has proved that people have lived there for over two millennia. The history of Kolkata begins when the English East India Company arrived in 1690. Job Charnock, an administrator with the Company is traditionally known as the founder of this city. However some academics say that Charnock is not the city's founder.

At that time Kolkata, ruled by the Nawab of Bengal Siraj-Ud-Daulah, had three villages. They were Kalikata, Govindapur and Sutanuti. The British in the late 17th century wanted to build a fort near Govindapur. This was to become more powerful than Dutch, the Portuguese, and the French. In 1702, the British completed the construction of old Fort William, which was used to station its troops and as a regional base. Calcutta was declared a Presidency City, and later became the headquarters of the Bengal Presidency. When regular fights with French forces started, in 1756 the British began to upgrade their fortifications. When this was protested, the Nawab of Bengal Siraj-Ud-Daulah attacked and captured Fort William. This led to the infamous Black Hole incident. A force of Company sepoys and British troops led by Robert Clive recaptured the city the next year. Calcutta became the capital of British India in 1772,. However, the capital shifted to the hilly town of Shimla during the summer months every year, starting from the year 1864.  Richard Wellesley, the Governor General between 1797–1805, helped in the growth of the city and its public architecture. This led to the description of Calcutta as "The City of Palaces". The city was a centre of the British East India Company's opium trade during the 18th and 19th century; locally produced opium was sold at auction in Kolkata, to be shipped to China.

References

Other websites

Former national capitals
Resurrection

Resurrection means bringing someone back to life after they have died.

Polytheistic religions
The idea of resurrection is found in writings of ancient polytheistic religions in the Middle East. Some Egyptian and Canaanite writings tell of gods being resurrected, such as Osiris and Baal.

In Greek mythology, many men and women were given eternal life by being resurrected from the dead. In their stories, some who came back to life as gods were Alcmene, Castor, Heracles, and Melicertes. But the Greek philosophers at that time did not believe in a physical rebirth.

Abrahamic religions

Christianity 

Christians believe that Jesus Christ was resurrected. They also believe in resurrection for all people after they die. This is based on the Gospels and on Saint Paul's writings in the New Testament.  The resurrection of Jesus is the Christian belief that he returned to life by a miracle. He died by crucifixion on Friday and rose from his tomb to new life on Sunday morning. This belief is celebrated at Easter.

The resurrection of Jesus Christ is written about by the evangelists in the New Testament. They are the authors of the four Gospels in the New Testament.  Christians believe the resurrection is a central part of the Christian faith. Jesus died on the cross to save mankind.  When he was resurrected, Jesus defeated death.  He is alive forever and sitting at God's right hand on a throne. This gives Christians the hope of a new life after death. This is because his resurrection mirrors the future for all Christians after they die.

With Jesus Christ and with humans, the Bible shows that the resurrected body is changed from the original.  This is because the human body, while alive, is weak and frail.  But, the resurrected person lives for ever.

All four Gospels tell about Jesus being raised from the dead. They also write about three times that Jesus brings a dead person back to life:
 Daughter of Jairus. Jairus, a patron of a synagogue, asks Jesus to heal his daughter, but while Jesus is on the way, Jairus is told his daughter was dead. Jesus tells him she was only sleeping, and wakes her with the words Talitha kum.
 The Young Man from Nain. A young man, the son of a widow, was on the way to be buried in Nain. Jesus sees the widow crying and so he tells her not to cry. Jesus tells the dead man inside to get up, and he does so.
 The Raising of Lazarus. A close friend of Jesus who had been dead for four days is brought back to life. Jesus goes to his grave and commands him to get up.

Islam 
In Islam, the Quran refers to a bodily resurrection of all those who have died.
This will be followed by a final time of trouble and eternal division of the righteous and wicked. Islamic apocalyptic literature describing Armageddon is often known as The Great Massacre or ghaybah in Shī'a Islam. The righteous are rewarded with the pleasures of Jannah (Paradise), while the unrighteous are punished in Hell.

Science 
According to Alcor, resurrection of legally dead people will be possible in the far future. They are using cryonics to preserve some legally dead people until the invention of the resurrection.

References 

Theology
Afterlife
Fuel

A fuel is a substance that is changed in some way to produce heat, electricity, or other forms of energy. This is usually by being burnt, although there are exceptions, such as nuclear fuel. Fuel can be divided into two main types: fossil fuels and other fuels.

Fossil fuel 

There are several kinds of fossil fuels:
 coal
 oil and products that are refined from oil (gasoline, diesel, kerosene)
 natural gas
Some people do not want us to use fossil fuels because they may pollute the environment. Because all fossil fuels are made out of carbon, burning them makes carbon dioxide. Some people think that too much carbon dioxide in the air may cause a greenhouse effect. Fossil fuels are also non-renewable, or renew extremely slowly (thousands of years). This means that we will eventually run out of fossil fuels.

Other fuels 
Other fuels are not made from fossils. Some of these, like nuclear and hydrogen, do not have carbon in them. Others, like wood or ethanol, do have carbon in them. Some examples of these fuels are:
 Nuclear fuel (uranium, plutonium, thorium, etc.)
 Hydrogen
 Extracted from the wind
 Biofuels from biomass
 Firewood
 Biodiesel (a diesel-type fuel made from plants)
 Ethanol (made from grains or other plants)
These fuels are renewable. This means that we can make more of them if we run out. For instance, if we run out of ethanol, we can grow some more corn and make some more ethanol.

Other websites

Fuel
Latvia

Latvia is a country in Northern Europe. The capital is Riga. It is one of the Baltic States, together with Estonia in the north and Lithuania in the south. Latvia's neighbours to the east are the countries Russia and Belarus. Latvia is split into four parts called Kurzeme, Vidzeme, Zemgale, and Latgale.

People from Latvia are called Latvians. They speak the Latvian language, which is a little like the Lithuanian language, though not close enough to be understood.

History 
Latvia was settled by the Baltic tribes thousands of years ago. They mainly fished, hunted, and traded.

German traders and crusaders came to Latvia at the end of the 12th century. Latvians lost control of their homeland. Over the next 800 years, Germans, Danes, Swedes, Poles, and Russians all invaded Latvia. Latvia finally became independent in 1918.

During the all time before the World War I the aristocracy were mainly  German.

During the Great Northern war (1700-1721) modern-day Latvia became the part of the Russian empire. There were organized Courland and Livonia governorates.

In 1940 Latvia became Soviet republic and joined to the Soviet Union.
It was under Nazi occupation during the World War II in 1941-1944. 

After the war a lot of factories were opened. Latvia became one of the successful Soviet republics.

In 1991 the Soviet Union was destroyed and new Latvian republic was declared.

Politics  
In Copenhagen on 13 December 2002, Latvia and nine other countries were invited to join the European Union. On 20 September 2003, Latvians held an election to vote on joining. Two thirds of Latvians voted to join, and on 1 May 2004 Latvia became a member of the EU.

Latvia has been a NATO member since 29 March, 2004.

International rankings

Related pages
 Latvia at the Olympics
 Latvia national football team
 List of rivers of Latvia

References

Other websites 

 Latvian Government official site

 
European Union member states
1991 establishments in Europe
Malta

Malta is a country in the European Union and considered part of Southern Europe. It is an island near the center of the Mediterranean Sea, south of Sicily. The capital of Malta is Valletta. Around 500,000 people live in Malta and it is one of the most densely populated countries in the world. Malta is 316 sq km, which makes it one of the smallest countries. Its many cities and towns grew close to each other over time.

Language 
Maltese is the national language of Malta and is influenced by Greek due to Magna Grecia settlements in Sicily.  Maltese and English are the official languages in line with the constitution of the country. A majority of the people of Malta can speak three languages; Maltese, English and Italian.

Money 
Malta had its own currency, called the Maltese Lira until 2008. The Maltese Lira was better known as the Maltese Pound because of the strong links to the United Kingdom. One Maltese Lira consisted of 100 cents. In 2008 Malta joined the Euro countries in adopting the Euro as the National Currency.

History 
People have lived in Malta since at least 5200 BC. The island has some key archaeological sites dating from early times.

Malta became well known as the base of the Knights Hospitaller. They moved to Malta after being forced to leave Palestine and then Rhodes, in Greece. In 1565 they survived a great attack by the Ottoman Empire. The history of the knights at Malta continued the strong Roman Catholic beliefs in the country that were started by the Norman and Spanish rulers.

In 1798, Napoleon took control of Malta. The French rule was not popular and in 1800 Maltese rebels invited the British Royal Navy to come to the island. This led to 200 years as a British colony and independent Commonwealth member.

During World War II, Malta was attacked this time by the Axis forces. The entire island was symbolically given the George Cross for heroism.

Malta became independent in 1964 and a republic in 1974. In 2004 Malta joined the European Union and in 2008 Malta joined the Euro.

Notes

Other websites 
 Maltese Relocation and Travel Guide
 Malta travel guide and information 
 Malta Wiki - Malta Popular Encyclopedia 
 Malta holidays and hotels
 Malta travel guide
 Malta
 Malta Travel Guide 

 
Italian-speaking countries
European Union member states
Phoenician colonies
1974 establishments in Europe
List of Soviet Union-related topics



Lists of people 

List of Premiers of the Soviet Union
List of Russians

A 

 AK-47

B 
 
 Baltic states
 Bolshevik

C 
 Central Asia
 Cold War
 Constructivism
 Communism
 Communist Party of the Soviet Union
 Comrade
 Collective farming
 Collectivisation in the USSR

E 
 Eastern Front (World War II)

G 
 Glasnost
 Great Soviet Encyclopedia

H 
 Hero of the Soviet Union
 History of the Jews in  Russia and Soviet Union
 History of the Soviet Union (1985-1991)
 Holodomor

K 
 Kolkhoz

M 
 Marxism–Leninism
 Moscow Metro

O 
 October Revolution

P 
 Palace of Soviets

R 

 Red Army
 Republics of the Soviet Union
 Russian Civil War

S 
 Socialism
 Soviet
 Soviet (council)
 Soviet people
 Soviet Union
 Soviet Union national bandy team
 Soviet Union national football team
 Soviet Union national ice hockey team
 Sputnik programme
 State Anthem of the Soviet Union

V 
 Volga Germans

W 

  Warsaw Pact Organization
 White movement
 World War I
 World War II

Geography-related lists
Comoving distance

In normal cosmology, 'comoving' distance or 'proper distance' is one of several distances measured by cosmologists to define distances between objects.

Method 
To talk about the shape of the Universe, scientists want to forget that the Universe is expanding. So they separate the shape from time and pretend that the Universe is not expanding. They remember that, really, the Universe is expanding, but they write this in a variable called the scale factor. Then, the distances they talk about, while putting the scale factor to the side, are called comoving distances. When they think about the Universe using comoving distance, they think of the Universe as not expanding. This way, some calculations are easier.

Purpose 
When the part of the Universe which we can see today started, it was very small. Everything in this part of the Universe was much closer together than today. It was also very hot and photons (particles of light) were moving in different directions. Light moves very fast, but the light speed is limited and the Universe was expanding very fast.

Comparison 
Think of two ants on the surface of an expanding balloon. One ant starts moving towards another, but the balloon itself is also expanding. After a long time the balloon starts expanding more slowly. Eventually one ant reaches another. That's like photons in our universe. Some of the light from the stars you see at night traveled for billions of years to reach your eye. Surprisingly, it started very close to where you were (or the atoms of which your body consists), but just could not keep up with the universe expansion. Of course, if something else started out very close to where you were, but was not traveling toward you, it would be very far away from you now because of the expansion. 

Cosmology
Lisbon

Lisbon is the capital city of Portugal. It is the largest city of Portugal. The city has a population of about half million people. In Lisbon's urban area live around 2.8 million people, being the 10th-most populous urban area in the European Union. 
Lisbon is placed on the right bank (western) of the Tagus River, near the outfall. It has a pleasant climate and has about 220 days of sunshine each year. There are many beautiful beaches close to the city. There are also many seafood restaurants, historical sites and monuments. Lisbon is one of the oldest cities in the world.

References

Other websites 
 Official page of the city 
 Lisbon Photos a collection of Photos, showing Lisbon as it is to visitors.
 Lisbon Tourist Guide and Information

Phoenician colonies
 
719 establishments
Establishments in Portugal
Surfing

Surfing is a water sport done in the ocean or sea. The surfer uses their surfboard to catch a wave and ride in towards the shore.

Surfing was invented by the Polynesians at least 4000 years ago. It has become a popular sport among both men and women of all ages. With lifestyles and regimens freer than those of most sports, surfers comprise a unique culture. Though surfing is practiced in many other Pacific nations, its center remains Hawaii, where many rounds of the international surfing championships (the ASP) are held annually. Surfing is popular in Australia, the US, and Northern Europe.

Related pages

Skimboarding
Windsurfing
Lyon

Lyon (Arpitan: Liyon) is a city in the southeast of France. It is the third-largest city in the country (behind Paris and Marseille), with about 513,000 people living there in 2015. It is the second largest metropolis, or metro area, in France (behind only that of Paris), with about 2.3 million people in 2014. 

In ancient history, the name of Lyon was Lugdunum. Someone who lives in Lyon is called a Lyonnais (male) or a Lyonnaise (female) in French.

Lyon has a humid subtropical climate (Cfa in the Koeppen climate classification). It is between the Rhône and the Saône. It is about  west of the Italian border. 

The central part of Lyon, located on the peninsula between the Rhône and the Saône, was named a World Heritage Site by UNESCO.

Famous people from Lyon 
 The Lumière Brothers who created cinema
 Paul Bocuse, a world renowned chef

Sports 
Famous sports clubs from Lyon are:

 Olympique Lyonnais: The local football team that plays in Ligue 1
 ASVEL: The local basketball team
 LOU: (Lyon Olympique Universitaire) The local rugby team

Education 
 École Centrale de Lyon
 École pour l'informatique et les nouvelles technologies
 École pour l'informatique et les techniques avancées
 École spéciale de mécanique et électricité
 EMLYON Business School
 E-Artsup
 Institut Polytechnique des Sciences Avancées
 Institut supérieur européen de gestion group
 Institut supérieur européen de formation par l'action
 Sup'Biotech
 Web@cademie

References

Departmental capitals in France
 
Regional capitals in France
World Heritage Sites in France
Natural gas

Natural gas is a mixture of gases. It consists mainly of hydrocarbons. The main component is methane. Natural gas is often found in the ground, either alone or together with petroleum. Landfills and natural processes produce a little methane. Usually it is transported to users in a pipeline.

Most natural gas is burnt as a fuel to produce energy. It burns with a clean blue flame, causing little pollution.

Natural gas is burned to produce electricity, to cook and to heat buildings. It is also used as fuel for natural gas vehicles for transport. When natural gas is burned in a power station it boils water into steam that spins a steam turbine that turns a generator to make electricity. Some power stations use natural gas in a gas turbine. 

Natural gas is also converted into many different industrial chemicals. It is the most common feedstock for making pure hydrogen. Hydrogen is used as fuel in fuel cells, and to make ammonia. Ammonia is used as a fuel, as a fertilizer for crops, and for making many other things. Natural gas is also converted into monomers to make many plastic products.

Related pages

Fossil fuel
Coal
non-renewable resource

Other websites 
History of using natural gas from the U.S. Department of Energy

References 

Fossil fuels
Hydrocarbons
Material

Material is what everything that you can touch is made of. Even material that is too small to touch, is called material. We use materials to make things. We can also call material "physical substances."

Raw material is materials such as ores which we can clean and mix with other materials to make another material like steel, for example. Cotton is a raw material used to make textiles, which are materials to make clothes.

Some important materials

 Metals
 Steel
 Aluminum
 Copper
 Gold
 Polymers
 Rubber
 Plastic
 Ceramics
 Glass
 Cement
 Stone
 Textiles
 Cotton fabric
 Wool fabric
 organic materials
 Leather
 Bone
 Paper
 Lumber/wood
 Glue
 Composites
 Fiberglass
 Concrete
Neuron

A neuron (or neurone) is a nerve cell that carries electrical impulses. Neurons are the basic units of our nervous system. 

Neurons have a cell body (soma or cyton), dendrites and an axon. Dendrites and axons are nerve fibers. There are about 86 billion neurons in the human brain. Almost all brain cells are neurons. The human brain has about 16 billion neurons in the cerebral cortex. The neurons are supported by glial cells and astrocytes.

Neurons are connected to one another, but they do not actually touch each other. Instead they have tiny gaps called synapses. These gaps are chemical synapses or electrical synapses which pass the signal from one neuron to the next.

Neuron ( link )

Types of neurons

By connection 
There are three classes of neurons: motor neurons, sensory neurons and interneurons.
 Sensory neurons carry information from tissues and organs into the central nervous system.
 Motor neurons transport signals from the central nervous system to the effector cells.
 Interneurons connect neurons within the central nervous system.

By function 
Sensory neurons carry signals from sense organs to the spinal cord and brain.
Relay neurons carry messages between sensory or motor neurons and the central nervous system
Motor neurons carry signals from the CNS to muscles, motor neurons are connected to the relay neurons. The signal passes between the neurons via synapses. Synapses are microscopic voids between cells where chemicals are released from the axon terminal of one cell to specialized chemical receptors on the dendrite of the receiving cell.

Cell division 
Mature neurons never divide: that is the general rule. They do not undergo cell division. In most cases, neurons are generated by special types of stem cells. A type of glial cell, called astrocytes, have also been seen to turn into neurons. In humans, neurogenesis (the origin of new nerve cells) largely ceases during adulthood  but in two brain areas, the hippocampus and the olfactory bulb, there is strong evidence for substantial numbers of new neurons.

The largest part of the human brain by far is the neocortex. It has at least ~1010 (10 trillion) neurons which stay with us from birth to death.

References

Related pages 
Brain cell

Other websites 
 Fibrinogen found to inhibit EGFR in neuronal cells Blood clotting protein may inhibit spinal cord regeneration 
 Cell Centered Database  UC San Diego images of neurons.
 High resolution neuroanatomical images of primate and non-primate brains .

Anatomy of the nervous system
Cells
Hindu–Arabic numeral system

The Hindu–Arabic numeral system, sometimes known as Hindu–Arabic numbers, is the system of numbers used by almost all the world today. It is a positional notation system. This system has ten basic symbols, they are 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9. It represent numbers in the decimal number system. The Hindu–Arabic numeral system was first developed by the Hindus. Later, It was introduced to the western world by the Arabs. The Hindu–Arabic numeral system is one of the few numeral systems that use a place value system. This system is now commonly used all over the world.

They originated in India in the 6th or 7th century and were introduced to Europe through the writings of Middle Eastern mathematicians, especially al-Khwarizmi and al-Kindi, about the 12th century.  They are very different from previous methods of counting, such as the abacus, and paved the way for the development of algebra.  In the past many other systems were used. Fibonacci popularized the Hindu–Arabic numeral system to the Western World.

References 

Mathematics
Numerals
Point (geometry)

A point is a precise position in space. Imagine touching a piece of paper with a sharp pencil or pen, without making any sideways movement. We know where the point is, but it has no size to speak of.

In geometry, a point has no size, but has a position. This means it has no volume, area or length. We usually represent a point by a small cross 'X' or by a small dot (a small, round shape). Points are always labelled by capital letters (A, B, C...X, Y, Z). It is one of the most fundamental but undefined terms in geometry.

In general, two points can be:
 Coincident (they are one and the same)
 Not coincident (they are not one and the same)
and are always:
 Coplanar (on the same plane)
 Colinear (on the same line)
 Concyclic (on the same circle)

Three points can be:
 Colinear
 Coincident
 Not coincident
 Not colinear
and are always:
 Coplanar
 Concyclic

Four points can be: 
 Coplanar
 Colinear
 Coincident
 Not coincident
 Not colinear
 Not coplanar

Related pages 

 Line
 Plane

References 

Geometry
Line

A line is the path of one point moving. A line has length but no width. A line is a type of geometric figure.

A line is made up of an endless number of points.

Straight and curved lines 

A line can be straight or curved. In geometry, the word line means a straight line. A straight line is the shortest distance between two points. A straight line is the line traced by a point moving in a direction that does not change.

A curved line is sometimes called a curve. The edge of a circle is not straight and is an example of a curve.

Line segments 
A line segment is part of a line. Here is an example of a straight line segment:

Naming lines 
Lines can get their names from any two points on the line. For example, if a line contains two distinct points, named  and , then the line can be called either , or .

Sometimes, lines are also named with just one symbol. In which case, a letter such as  might be used.

Two lines 
Two lines can be:
 Parallel: Two lines are parallel if they are on the same plane and they never touch.
 Concurrent: Two lines are concurrent if they touch on one point.
 Coincident: Two lines are coincident if they are made of the same points.
 Perpendicular: Two lines are perpendicular if they make four right angles where they touch.
 Skew: In Euclidean space, two lines are skew if they are not parallel but they never touch.

Related pages
 Linear function
 Point (geometry)
 Plane (mathematics)

References 

Basic English 850 words
Geometry
Angle

When two straight lines come together, they make an angle. The two lines are called the sides of the angle, and they meet at a point. A flat surface (called a plane) also forms an angle when it meets another.

To represent an angle, Greek letters such as  (alpha),  (beta),  (gamma) and  (theta) are sometimes used. An angle indicates the space between its sides, or the amount of rotation needed to make one side coincide the other.

To measure the size of an angle, we use units called degrees. A degree is a standard unit and we use the symbol ° after a number to show that it is a number of degrees. We can use a decimal number or a fraction for part of a degree, but a degree can also be divided into 60 minutes (1° = 60'), and a minute can be divided into 60 seconds (1' = 60"). So 22.5°, 22° and 22° 30' are all the same angle.  

In mathematics, angles can also be (and often are) measured in radians instead of degrees, by using the conversion factor  (for example, ). Yet another unit of angle is gradian, with  . 

Angles are studied in geometry, where an angle where edges meet is often called a vertex. For example, the three sides of a triangle are its edges and two of the edges meet at each vertex. Similarly, two of the six sides (or faces) of a cube meet at each of its twelve edges, and three edges meet at each of its eight corners (or vertices, which is the plural version of vertex).

Types of angles

 In a zero angle the lines lie one upon the other thus creating a 0° angle aka the zero angle.

 An angle greater than 0° but less than 90° is called an acute angle.

 An angle of 90° is called a right angle.

 An angle greater than 90° but less than 180° is called an obtuse angle.

 An angle that measures 180° is called a straight angle.
 An angle greater than 180° and less than 360° is called a reflex angle.
 An angle that has a made or full circle/ completed 360° is called a  full or complete angle.

Supplementary angles are two angles with the sum equal to 180°, and complementary angles are two angles with the sum equal to one right angle (90°). On the other hand, two angles that sum to one full circle (360°) are sometimes called explementary angles, or conjugate angles.

People usually use a protractor to measure and draw angles. Sometimes, people use a 360° protractor to measure angles.

Related pages 

 Sun angle

References

 
 
 
Basic English 850 words
List of walls

This is a list of famous walls.

Lists
List of vegetables

Some vegetables which are botanically fruits (such as tomatoes) are considered to be vegetables in the culinary (eating) sense. This is why they appear in this article. For sources, see individual pages.

artichoke
aubergine (eggplant)biologically a fruit but taxed as a vegetable 
 asparagus
legumes 
alfalfa sprouts
azuki beans (or adzuki)
bean sprouts
black beans
black-eyed peas
borlotti bean
broad beans
chickpeas, garbanzos, or ceci beans
green beans
kidney beans
lentils
lima beans or butter bean
mung beans
navy beans
peanuts
pinto beans
runner beans
split peas
soy beans
peas
mange tout or snap peas
broccoflower (a hybrid)
broccoli (calabrese)
brussels sprouts
cabbage
kohlrabi
Savoy cabbage 
red cabbage
cauliflower
celery
endive
fiddleheads 
frisee
fennel
greens
bok choy
chard (beet greens)
collard greens
kale
mustard greens

herbs 
anise
basil
caraway
coriander 
chamomile
daikon
dill
fennel
lavender
cymbopogon (also known as lemongrass)
marjoram
oregano
parsley
rosemary
thyme
lettuce 
arugula
mushrooms (actually a fungus, not a plant)
nettles
New Zealand spinach
okra
onions
chives
garlic
leek 
onion
shallot
scallion (spring onion UK, green onion US)
peppers (biologically berry, but taxed as vegetables)
bell pepper
chili pepper
jalapeño
habanero
paprika
tabasco pepper
cayenne pepper
radicchio
rhubarb
root vegetables
beetroot (UK) beet (US)
mangel-wurzel: a variety of beet used mostly as cattlefeed
carrot
celeriac
corms
eddoe
konjac
taro
water chestnut
ginger
parsnip
rutabaga
radish
wasabi
horseradish
 daikon or white radish
tubers
jicama
jerusalem artichoke
potato
sweet potato
yam
turnip
salsify (Oyster Plant)
skirret
sweetcorn 
topinambur
squashes (biologically fruits, but taxed as vegetables)
acorn squash
bitter melon
butternut squash
banana squash
courgette (UK), Zucchini (US)
cucumber (biologically fruits, but taxed as vegetables)
delicata
gem squash
hubbard squash
marrow (UK) Squash (US)

spaghetti squash 
zucchini 
spinach
tat soi
tomato (biologically a fruit, but taxed as a vegetable.)
watercress

References

Other websites 
 Lists of vegetables
Vegetables Name List 

Food-related lists
List of shipwrecks

This list of shipwrecks is of those sunken ships whose remains have been found.

 Aarhus Historic Shipwreck
 Admiral Graf Spee
 VOC ship Amsterdam
 SS Andrea Doria, 1956
 USS Arizona, Pearl Harbor
 VOC ship Batavia
 Bendigo, North Carolina, United States
 Bismarck battleship
 Breadalbane, 1853
 Carnatic shipwreck, Red Sea
 USS California (later San Diego), Long Island
 USS Eagle, Lake Champlain, New York
 Elingamite, New Zealand, 1902
 SS Edmund Fitzgerald, Lake Superior, 1975
 Cape Gelidonya
 Giglio Island, Etruscan wreck
 HMS Hampshire
 HMS Hood
 HMS Hussar
 Iria
 I-18tou midget submarine
 I-52
 Russian submarine Kursk
 Lady Elgin, Chicago, Illinois
 HMT Lancastria
 RMS Lusitania
 Mahdia
 Mary Celestia
 Mary Rose
 Medusa, French passenger ship of west Africa in 1816.
HMS Montague, Lundy Island, England
 USS Monitor
 CSS Muscogee', Georgia, United States
 Nola
 SS Richard Montgomery
 wreck of Rochelongue, France
 Scharnhorst, Norway
Nuestra Senora de Atocha -  Spanish galleon which sank in 1622 and was found on July 20, 1985 40 miles off the coast of Key West, Florida by treasure hunters who soon began to raise $400 million in coins and silver.   
H.M.T. Rohna American troop carrier in WWII
 USS Scorpion
 Seattle, Norway
 Snow Squall
 USS Thresher
 USS Ticonderoga, Lake Champlain, New York
 RMS Titanic
 Uluburun
 Struma, Black Sea
 HMS Wasa, Stockholm, Sweden
 Vicar of Bray
 SS Yongala, Townsville, Australia
 VOC Zuytdorp, Australia, 1712
 RMS Empress of Ireland, Saint Lawrence River
The White Ship, 1120

Further reading
 A. J. Parker, Ancient shipwrecks of the Mediterranean and the Roman provinces (Oxford 1992).

Transport lists
Ships
List of endangered languages

A list of endangered languages (with fewer than 1000 speakers or with very fast decline).

In order to judge if a language is actually endangered, the number of speakers is less important than the distribution among age cohorts. There may be 200,000 mother tongue speakers of the Breton language over 50 years of age, but fewer than 2,000 under 25 years of age - thus it is likely Breton will die out in the next half century. On the other hand, while there are 30,000 Ladin language speakers left, almost all children still learn it as their mother tongue - thus Ladin is not endangered in the 21st century.

 This page should include a link to the language's page, geographical localization and an approximate number of speakers

Americas 
 Michif, spoken by fewer than 1,000 people in western Canada
 indigenous languages of Canada:
 Abenaki, 10 speakers
 Beaver, 300 speakers
 Cayuga, 360 speakers
 Delaware (Munsee), fewer than 10 speakers
 Han, few speakers
 Hare, 600 speakers
 Onandaga, fewer than 100 speakers
 Oneida, 200 speakers
 Potawatomi, 100 speakers
 Sarcee, 10 speakers
 Seneca, 25 speakers
 indigenous languages of the USA:
 Hawaiian language, Hawaii

Asia 
 Ainu, Northern Japan, 15 speakers
 Aramaic, Lebanon, Kurdistan
 Chukchi, Siberia, circa 10,400 speakers (2001)
 Udmurt, various parts of Russia
 Northern indigenous peoples of Russia
 Beechistani ,Somewhere in Northern India(Beechistaan), 6 speakers
Sanskrit, Nepal-India, Less than 500 speakers, According to Indian history, Sanskrit is the mother of all Indo-European languages.
Athpahariya language, Athpahariya
Bahing language, Bahing
Barām language, Barām
Chepang language
Kumāle language, Kumāle
Kusunda language, Kusunda
Surel language, Surel

Australia 
 all aboriginal languages

Europe 
 European Union
Alsatian (France) very fast decline
 Aragonese (Spain) very fast decline
 Aromanian (Greece) very fast decline
 Basque (Spain and France) very fast decline
 Breton (France) very fast decline
 Catalan (France) very fast decline
 Corsican (France) very fast decline
 Catalan (Italy) very fast decline
 South Italian Greek (Italy) very fast decline
 Italkian (Judeo-Italian) (Italy) probably extinct
 Molise Slavic (Italy) very fast decline
 Occitan (France) very fast decline
 Sami languages, (Scandinavia), some having fewer than 100 speakers
 Scottish Gaelic (United Kingdom) very fast decline
 Lower Sorbian, (Germany) very fast decline
 West Flemish (France) very fast decline
 Yevanic (Judeo-Greek) (Greece) probably extinct
 Outside of the European Union
 Belarusian, very low usage in Belarus
 Istro-Romanian, Istria Croatia, 500 speakers
 Krimchak (Judeo-Crimean Tatar)
 Livonian, Estonia, 35 speakers
 Mordvin (Russia), steady decline
 Erzya language
 Moksha language
 Votian, Russia, 50 speakers

Related pages
 endangered language
 list of extinct languages
 Language families and languages
 Language policy

References

Other websites 
 UNESCO Red Book of Endangered Languages

Language-related lists
Africa
List of mental disorders

The following is a list of mental disorders.
List of color topics

This is a list of color topics.

Lists
Lists of astronomical objects

This is a partial list of the various lists of astronomical objects which either exist, or should exist, in Wikipedia.

 List of stars
 List of nearest stars
 List of brightest stars
 List of planets
 List of planetary moons
 List of exoplanets
 Minor planets:
 List of asteroids
 List of comets
 List of trans-Neptunian objects
 List of stars with confirmed extrasolar planets
 List of variable stars
 List of semiregular variable stars
 List of pulsars
 List of quasars
 List of blazars
 List of gamma-ray bursters
 List of black holes
 List of galaxies
 List of nearest galaxies
 List of satellites of the Milky Way
 List of traditional star names
 List of globular clusters
List of stars

The following is a small list of stars. On this list, stars should be placed by their English wiki title, unless a common name is clearly more used.

40 Eridani
51 Pegasi
61 Cygni
70 Virginis

A
Achernar
Acrux
Albireo
Aldebaran
Algol
Alioth
Alniyat
Alpha Arietis (Hamal)
Alpha Centauri (Rigil Kentaurus)
Alpha Herculis ( Ras Algethi)
Altair
Aludra
Antares
Arcturus
Arrakis
Avior

B
Barnard's star
Becrux (Mimosa)
Beta Arietis (Sharatan)
Beta Aurigae (Menkalinan)
Beta Centauri (Hadar) 
Beta Columbae
Beta Tauri (Elnath)
Betelgeuse

C
Canopus
Capella
Castor
Cygnus X-1
Deneb

D 
Delta Cephei

E
Epsilon Eridani
Epsilon Indi
Eta Carinae

F

Fomalhaut

G
GJ 1061
GRB 970228

H
HE0107-5240

K
Kapteyn's Star
Kruger 60 A
Kruger 60 B

L
Lacaille 9352
Lalande 21185

M
Meissa
Miaplacidus
Mintaka
Mira
Mirach
Mizar

N
Nemesis (hypothetical)

P
Pistol Star
Polaris
Pollux
Procyon
Proxima Centauri

R
Regulus
Rigel
Ross 128
Ross 154
Ross 248
RR Lyrae

S
Saiph
Sirius
Spica
Sun (Sol)
Stephenson 2-18

T
Tau Ceti
Thuban

U
Upsilon Andromedae

V
V886 Centauri (BPM 37093)
Vega
VY Canis Majoris

W
Wolf 359

Related pages 
List of nearest stars
Star formation
Star
Stellar evolution
Stellar classification
List of nearest stars

This list of the nearest stars to Earth is by distance in light years (ly). These distances are taken from parallax data determined by the Research Consortium on Nearby Stars (or Recons). 
The sources for this information were the Yale Parallax Catalog [Y], Hipparcos [H], Soderhjelm 1999 [S], Tinney 1996 [T]. Stars move, and so distances are as at present only.

Some 52 star systems beyond our own, the Solar System,  lie within  of the Sun. These systems contain 63 stars. 50 of these are red dwarfs, by far the most common type of star in the Milky Way. Much more massive stars, such as our own, make up the remaining 13. In addition to these "true" stars, scientists have identified 11 brown dwarfs (objects not quite massive enough to fuse hydrogen), and four white dwarfs. White dwarfs are extremely dense collapsed cores that remain after stars such as our Sun have exhausted all fusible hydrogen in their core and have slowly shed their outer layers. Despite the relative proximity of these 78 objects to Earth, only nine are bright enough in visible light to be visible to the naked eye from Earth, 6.5 apparent magnitude. All of these objects are currently moving in the Local Bubble, a region within the Orion–Cygnus Arm of the Milky Way.

List 
 Sun – about 8.2 light minutes from Earth
 Alpha Centauri star system – 4.24 to 4.36 ly
 Proxima Centauri – 4.24 ly [YH]
 Alpha Centauri A – 4.36 ly [YS]
 Alpha Centauri B – 4.36 ly [YS]
 Barnard's Star – 5.96 ly [YH]
 WISE 1049-5319 – 6.5 ly, aka Luhman 16, a binary of two brown dwarf stars
 Wolf 359 – 7.78 ly [Y]
 Lalande 21185 – 8.3 ly [YH]
 Sirius star system
 Sirius A – 8.58 ly [YH]
 Sirius B – 8.58 ly [YH]
 Luyten 726-8 – 8.73 ly 
 UV Ceti – 8.73 ly [Y]
 Gl 65 B – 8.73 ly [Y]
 Ross 154 – 9.68 ly [YH]
 Ross 248 – 10.32 ly [Y]
 WISE 1506+7027 – 16.85 ly
 Epsilon Eridani – 10.52 ly [YH]
 Lacaille 9352 – 10.74 ly [YH]
 Ross 128 – 10.92 ly [YH]
 EZ Aquarii star system
 EZ Aquarii – 11.26 ly [Y]
 Gl 866 B – 11.26 ly [Y]
 Gl 866 C – 11.26 ly [Y]
 Procyon star system
 Procyon A – 11.4 ly [YH]
 Procyon B – 11.4 ly [YH]
 61 Cygni star system
 61 Cygni A – 11.4 ly [YH]
 61 Cygni B – 11.4 ly [YH]
 Struve 2398 (Gliese 725) star system
 Struve 2398 A – 11.52 ly [YH]
 Struve 2398 B – 11.52 ly [YH]
 Groombridge 34 (Gliese 15) star system
 Groombridge 34 A – 11.62 ly [YH]
 Groombridge 34 B – 11.62 ly [YH]
 Epsilon Indi – 11.82 ly [YH]
 DX Cancri – 11.82 ly [Y]
 Tau Ceti – 11.88 ly [YH]
 GJ 1061 – 11.92 ly [RECONS]
 YZ Ceti – 12.13 ly [YH]
 Luyten's Star – 12.36 ly [YH]
 Teegarden%27s_Star – 12 ly (discovered 2003)
 Kapteyn's Star – 12.77 ly [YH]
 AX Microscopium – 12.86 ly [YH]
 Kruger 60 star system
 Kruger 60 A – 13.14 ly [YS]
 Kruger 60 B – 13.14 ly [YS]
 Ross 614 star system
 Ross 614 – 13.34 ly [YS]
 Gl 234 B – 13.34 ly [YS]
 Gl 628 – 13.81 ly [YH]
 Gl 35 – 14.06 ly [YH]
 Gl 1 – 14.22 ly [YH]
 Wolf 424 star system
 Wolf 424 – 14.30 ly [Y]
 Gl 473 B – 14.30 ly [Y]

Related pages 
 Astronomy
 Star
 List of stars

References 

Lists of stars