'Courses' in the Bible

And it cometh to pass, in the going out of the priests from the sanctuary -- for all the priests who are present have sanctified themselves, there is none to watch by courses,

And he appointed, according to the order of David his father, the courses of the priests to their service, and the Levites to their charges, to praise and minister before the priests, as the duty of every day required: the porters also by their courses at every gate: for so had David the man of God commanded.

So the Levites and all Judah did according to all things that Jehoiada the priest had commanded, and took every man his men that were to come in on the sabbath, with them that were to go out on the sabbath: for Jehoiada the priest dismissed not the courses.

And Hezekiah appointed the courses of the priests and the Levites after their courses, every man according to his service, the priests and Levites for burnt offerings and for peace offerings, to minister, and to give thanks, and to praise in the gates of the tents of the LORD.

And next him were Eden, and Miniamin, and Jeshua, and Shemaiah, Amariah, and Shecaniah, in the cities of the priests, in their set office, to give to their brethren by courses, as well to the great as to the small:

Beside their genealogy of males, from three years old and upward, even unto every one that entereth into the house of the LORD, his daily portion for their service in their charges according to their courses;

Both to the genealogy of the priests by the house of their fathers, and the Levites from twenty years old and upward, in their charges by their courses;

And prepare yourselves by the houses of your fathers, after your courses, according to the writing of David king of Israel, and according to the writing of Solomon his son.

So the service was prepared, and the priests stood in their place, and the Levites in their courses, according to the king's commandment.