A Buddha is the holiest type of being in Buddhism, a teacher of God's and humans. The word Buddha means "enlightened one" in Sanskrit or Fully Awakened One in Pāli. 

It is also a title for Siddhartha Gautama. He was the man who started Buddhism. Sometimes people call him "the Buddha" or the "Shakyamuni Buddha". Other times, people call any person a Buddha if they have found enlightenment. If a person has not found enlightenment yet, but is very close to reaching it, then he is called bodhisattva.

Summary
Buddhists believe that there are many Buddhas. The most recent one was Gautama Buddha. People who will become Buddhas someday are called "bodhisattvas." 

Buddhists believe that the Buddha was enlightened, which means that he knew all about how to live a peaceful life and how to avoid suffering. He is said to have never argued with other people, but only said what was true and useful, out of compassion for others.

Some Buddhists pray to Buddhas, but Buddhas are not gods. Buddhas are teachers who help the people who will listen. A Buddha is a human being who has woken up and can see the true way the world works. This knowledge totally changes the person so that they can have a better life in the present and the future. A Buddha can also help a person achieve enlightenment. 

There are ideas which are said to lead someone to enlightenment. They are called the Dharma (Sanskrit) or "Dhamma" (Pāli), meaning "the way" or "the truth." Anyone can become a Buddha, but it is very difficult. He became Buddha under the peepal or "bodhi" tree at Bodhgaya in Bihar in what is now India.

Types of Buddhas

There is a special type of Buddha called a pratyekabuddha or "silent Buddhas". These Buddhas reached enlightenment on their own, but they did not teach others. 

Another type of Buddha is a samyaksambuddha. This is the best kind of Buddha because he is able to teach all living beings.

Seven Buddhas of the past
Buddhists believe that there have been many Buddhas in the past. There will also be many Buddhas in the future. Traditionally, seven Buddhas are given names.

Vipashyin Buddha
Shikhin Buddha
Vishvabhu Buddha
Krakucchanda Buddha
Kanakamuni Buddha
Kashyapa Buddha
Shakyamuni Buddha

Maitreya will be the next Buddha.

32 Signs of a Great Man
A Buddha is a person who has reached perfection. Some believe that there are 32 physical features of a Buddha; these are the 32 marks of a Great Man from Vedic brahmin folklore, but are mentioned in the Pāli canon. Some of these features are represented in art and sculpture. These are listed below.

 Flat feet
 Thousand-spoked wheel symbol on feet
 Long, slender fingers
 Flexible hands and feet
 Webbed fingers and toes
 Full-sized heels
 Arched insteps
 Thighs like a royal stag
 Hands that reach below the knees
 Sheathed male organ
 Equal height and stretch of arms
 Dark-colored hair
 Graceful and curly body hair
 Golden-hued body
 Ten-foot halo around his body
 Soft, smooth skin
 Soles, palms, shoulders, and crown of head well-rounded
 Area below armpits filled out
 Lion-shaped body
 Erect and upright body
 Full, round shoulders
 Forty teeth
 White, even, and close teeth
 Four pure white canine teeth
 Jaw like a lion
 Saliva that improves the taste of all food
 Long and broad tongue
 Deep and resonant voice
 Deep blue eyes
 Eyelashes like a royal bull
 White curl of hair (ūrṇā) that emits light between eyebrows
 Bump on the crown of the head

Related pages
 Siddhartha Gautama
 Bodhisattva
 Buddhism

References

 
Buddhist terminology

3. “Chapter 3 Buddhism. Origins and Fundamental Tenets. .” Religions in the Modern World: Traditions and Transformations, section written by Cathy Cantwell & Hiroko Kawanami., Routledge, 2016, pp. 75–78