Easton's Bible Dictionary: M. G. Easton, M.A., D.D.
An organized living creature endowed with sensation. The Levitical law divided animals into clean and unclean, although the distinction seems to have existed before the Flood (Gen. 7:2). The clean could be offered in sacrifice and eaten. All animals that had not cloven hoofs and did not chew the cud were unclean. The list of clean and unclean quadrupeds is set forth in the Levitical law (Dt. 14:3-20; Lev. 11).