'Courses' in the Bible

And David divided them into courses among the sons of Levi, namely, Gershon, Kohath, and Merari.

Now the children of Israel after their number, to wit, the chief fathers and captains of thousands and hundreds, and their officers that served the king in any matter of the courses, which came in and went out month by month throughout all the months of the year, of every course were twenty and four thousand.

Also for the courses of the priests and the Levites, and for all the work of the service of the house of the LORD, and for all the vessels of service in the house of the LORD.

And, behold, the courses of the priests and the Levites, even they shall be with thee for all the service of the house of God: and there shall be with thee for all manner of workmanship every willing skilful man, for any manner of service: also the princes and all the people will be wholly at thy commandment.