Buddha

n. (born Siddhartha Gautama) Nepali religious leader and the founder of Buddhism (c.563-c.483 BC); spiritual teacher; person who has reached full enlightenment

In Buddhism, a (Sanskrit: Awakened) is any being who has become fully awakened (enlightened), and has experienced Nirvana. In the Pali Canon and the Theravada tradition, the term 'buddha' usually refers to anyone who has become enlightened (i.e., awakened to the truth, or Dharma) on their own, without a teacher to point out the Dharma, in a time when the teachings on the Four Noble Truths or the Eightfold Path do not exist in the world. By comparison, those who awaken due to the teachings given by a Buddha are known as Arahants, a title also applied to Buddhas. Arahants and Buddhas are the same in the most fundamental aspects of Liberation (Nirvana), but differ in their paramis.
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Noun
1. founder of Buddhism; worshipped as a god (c 563-483 BC)
(synonym) the Buddha, Siddhartha, Gautama, Gautama Siddhartha, Gautama Buddha
(hypernym) mystic, religious mystic
2. one who has achieved a state of perfect enlightenment
(hypernym) saint, holy man, holy person, angel

n. Buddha, Indian religious leader and the founder of Buddhism; Indian spiritual teacher; person who has reached full enlightenment

(n.)
The title of an incarnation of self-abnegation, virtue, and wisdom, or a deified religious teacher of the Buddhists, esp. Gautama Siddartha or Sakya Sinha (or Muni), the founder of Buddhism.