Terefah and Nevelah - Two Categories of Animals That May Not Be Eaten

A terefah is an animal or bird possessing one a well-defined group of life-threatening body defects that will results in its death within twelve motnhs. The meat of an animal or bird that is terefah may not be eaten even if the animal was killed through ritual slaughter, or shechitah.

A nevelah, on the other hand, is the carcass of an animal or bird that did not undergo a proper shechitah.