Fara' was the first animal born to them (the Arabs) which they sacrificed.
Sunan Abi Dawud Book 16, Hadith 45
← Previous Hadith Prophet (ﷺ) sa saying: There is no fara' and 'atirah.

Sunan Abi Dawud Book 16, Hadith 44 Next Hadith → The Messenger of Allah (ﷺ) used to sacrifice goat out of every fifty goats.

Abu Dawud said: Fara' means the first baby camel born (to the Arabs). They used to sacrifice it for their idols, and then eat it, and its skin was thrown on a tree. 'Atira was a sacrifice made during the first ten days of Rajab.

Sunan Abi Dawud Book 16, Hadith 46