From ephemeros; diurnality, i.e. (specially) the quotidian rotation or class of the Jewish priests' service at the Temple, as distributed by families -- course.
see GREEK ephemeros
1. a service limited to a stated series of days (cf. German Tagdienst,Wochendienst); so used of the service of the priests and Levites: Nehemiah 13:30; 1 Chronicles 25:8; 2 Chronicles 13:10, etc.
2. "the class or course itself of priests who for a week at a time performed the duties of the priestly office" (German Wöchnerzunft): 1 Chronicles 23:6; 1 Chronicles 28:13, etc.; 1 Esdr. 1:2, 15; so twice in the N. T.: Luke 1:5, 8. For David divided the priests into twenty-four classes, each of which in its turn discharged the duties of the office for an entire week from sabbath to sabbath, 1 Chronicles 24:4; 2 Chronicles 8:14; Nehemiah 12:24; these classes Josephus calls πατριαί and ἐφημεριδες, Antiquities 7, 14, 7; de vita sua1; Suidas, ἐφημερία. ἡ πατριά λέγεται δέ καί ἡ τῆς ἡμέρας λειτουργία. Cf. Fritzsche, commentary on 3 Esdras, p. 12. (BB. DD. under the word