From ephemeros; diurnality, i.e. (specially) the quotidian rotation or class of the Jewish priests' service at the Temple, as distributed by families -- course.
KJV: There was in the days of Herod, the king of Judaea, a certain priest named Zacharias, of the course of Abia: and his wife was of the daughters of Aaron, and her name was Elisabeth.
NASB: In the days of Herod, king of Judea, there was a priest named Zacharias, of the division of Abijah; and he had a wife from the daughters of Aaron, and her name was Elizabeth.