Definitions for oxtailˈɒksˌteɪl
Random House Webster's College Dictionary
the skinned tail of an ox or steer, used as an ingredient in soup, stew, etc.
Origin of oxtail:
the skinned tail of cattle; used especially for soups
a cut of meat taken from the tail of a cow or calf; it requires long slow braising, and is used to prepare the classic oxtail soup