Emily Dickinson Lexicon

BEEF, n. [Fr. bœuf; beuf, an ox; Arm. bevin; It. bue; Sp. buey; Port. boy; W. buw; Corn. byuh, an ox; Ir. bo, a cow, plur. buaibh; L. bos, bovis; Gr. βους.]

1. An animal of the bovine genus, whether ox, bull, or cow; but used of those which are full grown or nearly so. In this, which is the original sense, the word has a plural, beeves.
2. The flesh of an ox, bull, or cow, when killed. In popular language, the word is often applied to the live animal; as, an ox is good beef; that is, well fattened. In this sense, the word has no plural.