(Sanskrit avatâra, literally: "descent", usually translated as "incarnation")
In hindu mythology, the appearance of a deity on Earth in human or animal form. This is not a reincarnation; rather, it is the voluntary assumption by the deity of physical form.
The phenomenon is particularly associated with the god Vishnu. Most famous of his avatars are Rama, the protagonist of the great epic Ramayana, and Krishna, one of the most popular deities of the hindu pantheon.
In the religious/philosophical didactic poem Bhagavad-Gita, Krishna explains the concept thus:
"Every time justice wanes and injustice waxes, I create myself anew. In each age, I am born again to protect the good, to destroy the wicked and to restore justice."