"Avatar", one definition

"Avatar. In Hinduism, an incarnation of Vishnu. Used more generally by occultists and theosophists to denote any divine incarnation".

"Vishnu. In Hinduism, one of the three major gods of the trimurti, the other two being Brahma and Shiva. Vishnu was originally a Vedic god who acquired prominence as a peaceful sky-god, protector of the universe. As a guide and friend of humankind, Vishnu was belived to have incarnated on several occasions (the number of incarnations varies from ten to thirtynine) in order to save the world in times of chrises. Among Vishnu's most famous incarnations were Rama (described in the Ramayana) and Krishna (described in the Bhagavad Gita). Many devotees also considered Gautama Buddha as an incarnation. Vishnu's final appearance as Kalki, at the end of the world, is still to come".

From "Dictionary of mysticism and the occult" by Nevill Drury, (1985).