[yak] n, pl yaks also yak [Tibetan gyagk] (1795): a large long-haired wild or domesticated ox (Bos grunniens syn. B. mutus) of Tibet and adjacent elevated parts of central Asia
[2]yak n [imit.] (1948) 1 slang: laugh
2. slang: joke, gag [3]yak also yack vi yakked also yacked ; yak.king also yack.ing [prob. imit.] (1949): to talk persistently: chatter [4]yak also yack n (1950): persistent or voluble talk