Monarchs were very common in history until the 19th century. Most European countries had monarchs in past centuries, but no longer have them. Some countries that still have monarchs have other leaders that actually have the power. Some countries elect their monarch instead of using inheritance, like the Holy Roman Empire and Malaysia.
Monarchs can also have monarchs of lower honour below them, e.g. an Empire could include several kingdoms, and a kingdom had several duchies or principalities, nations would rarely include all titles, usually going from duchy to kingdom instead of duchy to principality to kingdom. Prince/Princess means 'Ruler of a Principality' and 'son of king/queen'. Some other languages have separate words for them.
Unit
Unit means part of something. It could mean a unit of measurement, or a unit in an army.
Units sometimes means the digit in a number on the right, which is also called the "ones".
Some other ideas come from this word:
For example, a football team may be called "X United". This means that the town of X has come together to support the group.
In the BBC TV series Doctor Who, UNIT (UNified Intelligence Taskforce) is a military group on earth who battle invading aliens.
Uncle
An uncle is a name used in an extended family. An uncle is either a brother of one of someone's parents. That person is the uncle's nephew (male) or niece (female). An uncle's child is a cousin. A (also written as great-uncle or grand-uncle) is the brother of a grandparent. In some cultures an uncle is considered a close family member. Based on the old Chinese saying "the oldest son in the family is the father of the family" an uncle is often the head of a family. In many cultures no single word (such as uncle) describes both their parents' brothers. Instead there are words to describe a person's kinship to their mother's brother or a person's kinship to their father's brother. An uncle can also be someone not related by blood or marriage as in a term of endearment or respect. In this use uncle can also be part of a nickname such as Uncle Sam.
During the Middle Ages in western Europe, a maternal uncle played a particular role in the family. A young man was often closer to his maternal uncle (from or "little grandfather") than to his own father. Tacitus noted the Franks had very strong ties between a maternal uncle and his nephew. In Roman family relationships the "avunculus" had a responsibility to defend his nephews as well as his nieces. The maternal uncle relationship was an extension of the Roman kin system's strong brother-sister relationship.
A maternal or paternal relative is one who is related through their mother or father, respectively. For example a maternal uncle is a the subject's mother's brother.An in-law is a relationship that is not by blood, but instead by marriage. The in-law shares the in-law relationships of the spouses relatives. For example a uncle in-law could be the husband of the subject's Aunt.
Information
The word "information" is used in many different ways. Originally, it comes from a word that meant to give a form to something. Information is something that people can learn, know about, or understand. For example, a newspaper contains information about the world. This article contains information about "Information".
People who use computers often use the words "information" and "data" in the same way. There are special fields of study called "information science", "information technology" (IT), and data science.
In the 1970s and 1980s, some people gave a new, specific meaning to "information". At that time, the first computer databases were built. In computer science, "data" often means a kind of information that has not been checked. That means "data" has not been changed or fixed, and you may not be able to trust it. With the new meaning, "information" means data that has been checked and passed tests for what it must be. A person can trust that "information" is correct.
Information can only be correct and good enough to trust if there are very good and complete ways to check the data (data checking, validation or verification) and decide it is good enough (acceptance process). A person must know rules were used to check the data or trust the person who checked the data. If a person cannot tell that this was done, the information still seems to be data for that person, so that person must check the data again, in that general view about data.
The Information Age is a historic period.
Airport
An international airport is a large airport that airplanes can use to fly to and from other countries. A domestic airport is an airport which is usually smaller and only has airplanes coming from different places in the same country. Most international airports have shops and restaurants for airplane passengers to use.
An airport used by the military is often called an air force base or airbase. An aircraft carrier is a floating airbase.
Airports are made and operated for safety. Today, people must walk through a metal detector, a machine that can tell if metal goes through it. If it makes a noise, the officers will make that person take off all things on them that are metal. They also have X-ray machines that can look into luggage. If officers find items such as weapons, or anything that can be used to kill people, that item (and the person who has it) are taken away and possibly arrested. As well as this, passengers are not allowed to bring bottles or containers with over 100 ml of liquid onto the plane because they could be turned into bombs. Therefore, all water bottles must be emptied before entering the secured area.
Ice
Ice is the common name for frozen water. Other liquids, such as ammonia or methane or milk could be called ice when they freeze but they are called 'milk ice', for instance, instead of just 'ice'. Liquid water becomes solid ice when it is very cold. The freezing point is 0° Celsius (32° Fahrenheit or 273 kelvin).
Ice is commonly made in a home refrigerator or freezer. If water is put in a freezer and left for a while, the water gets very cold and will freeze solid, creating ice. Water can be placed into a copper (or other metal) container to cause it freeze into ice faster. Metals are good conductors of heat, so water can freeze faster than in a plastic ice tray.
Unlike other liquids, water expands as it freezes to become ice; so ice floats on water because ice has less density than water. This is very unusual - just about every other liquid gets more dense as it cools; water ice, however, is an important exception. Liquid water expands by about 9% as it becomes ice - it takes up more space. This is because the water molecules are actually farther apart instead of being closer together. The molecules in an ice crystal are arranged in a way that makes it less dense than liquid water.
If water in plumbing freezes, it can burst the water pipe. Water in glass bottles can make them explode when it freezes. Water freezing in rock cracks can expand enough to split hard rocks apart; this is an important geological weathering process that can wear down mountains and make rock into soil.
When materials are cooled their molecules vibrate less and compact together. When most materials reach a temperature called the freezing point, the molecules form a crystalline solid - although some materials (like glass and tar) do not crystallise at all but form super stiff fluids, which seem to be solid. Only Helium will not freeze; all other substances will freeze if cold enough, but fluids like cooking oil, antifreeze, petrol (gasoline), nitrogen, etc. freeze at temperatures that most people don't experience.