Noun
A beefsteak cut from the primal rib area of a bovine, with the rib bone attached to the steak cut. A bone-in rib steak.
Synonyms: cowboy steak, tomahawk steak
A similar cut from another animal.
(by extension) A bone-in or boneless cut of steak, either the rib or ribeye steak.
Source: en.wiktionary.org