Dictionary · Easton's 1897
Fast
The sole fast required by the law of Moses was that of the great Day of Atonement (q.v.), Lev. 23:26-32. It is called “the fast” (Acts 27:9).
The only other mention of a periodical fast in the Old Testament is in Zech. 7:1-7; 8:19, from which it appears that during their captivity the Jews observed four annual fasts.