Easton’s Bible Dictionary
Convocation: a meeting of a religious character as distinguished from congregation, which was more general, dealing with political and legal matters. Hence it is called an "holy convocation." Such convocations were the Sabbaths (Leviticus 23:2,3), the Passover (Exodus 12:16; Leviticus 23:7,8; Numbers 28:25), Pentecost (Leviticus 23:21), the feast of Trumpets (Leviticus 23:24; Numbers 29:1), the feast of Weeks (Numbers 28:26), and the feast of Tabernacles (Leviticus 23:35,36). The great fast, the annual day of atonement, was "the holy convocation" (Leviticus 23:27; Numbers 29:7).