Albert Barnes on Acts 11:27

And in these days. While Barnabas and Saul were at Antioch.

Came prophets. The word prophet denotes, properly, one who foretells future events. Mt 7:16. It is sometimes used in the New Testament to denote simply religious teachers, instructors sent from God, without particular reference to future events. To teach the people in the doctrines of religion was a part of the prophetic office; and this idea only was sometimes denoted by the use of the word. See Rom 12:6, 1Cor 12:10,28, 13:2,8, 14:3,5,24. These prophets seem to have been endowed in a remarkable manner with the knowledge of future events; with the power of explaining mysteries; and in some cases with the power of speaking foreign languages. In this case, it seems that one of them at least had the power of foretelling future events.

(b) "prophets" Acts 2:17, 13:1, Eph 4:11