Varaha

Varaha is an avatar or incarnation of Lord Vishnu. It is one of the 10 major incarnations (Dashavatar) of Lord Vishnu. Varaha is the third avatar out of the ten dashavatars.

Hiranyaksha's Crime
Once, there lived an asura named Hiranyaksha. He was born to Sage Kashyapa and Diti. ￼He grew up hearing tales about the other asuras getting slayed by the devas. He wanted revenge for what happened to his brothers. So, he performed a penance to Lord Brahma. Upon years and decades of meditating, Lord Brahma appeared before him and asked him for a boon. He requested that he should not be slain by any god, animal, human, etc.., but he forgot to mention the boar. So he went to conquer the heavens. Then he abducted the earth goddess, Bhudevi and hid her in Patala (underworld). Upon hearing the prayer of many mortals and also the earth goddess herself, Lord Vishnu decided to take the form of a boar and save the earth.

Slaying of Hiranyaksha and Rescuing Bhudevi
Lord Vishnu then went to Patala and confronted Hiranyaksha, who was holding Bhudevi captive. He slayed Hiranyaksha, ending his life. as he forgot to mention the boar, he was slain by a boar. Varaha, then rescued Bhudevi, lifting the earth on his tusks and bringing peace to the world.

Etymology
Varaha, in sanskrit, means 'boar' or 'wild boar'.