late 13c., "onward movement," from Old French cors (12c.) "course; run, running; flow of a river," from Latin cursus "a running race or course," from curs- past participle stem of currere "to run" (see current (adj.)).
Most extended senses (meals, etc.) are present in 14c. Academic meaning "planned series of study" is c.1600 (in French from 14c.). Phrase of course is attested from 1540s; literally "of the ordinary course;" earlier in same sense was bi cours (c.1300).