late 14c., "a moving, running, or flowing together; a gathering or accumulation," from Old French concours and directly from Latin concursus "a running together," from past participle of concurrere "to run together, assemble hurriedly; clash, fight," from assimilated form of com "together" (seecon-) + currere "to run" (from PIE root *kers- "to run").
From early 15c. as "an assembly, a throng." Sense of "open space in a built-up place," especially a gathering place in a railway station, etc., is American English, 1862. From French, English took concours d'élégance"a parade of vehicles in which the entrants are judged according to the elegance of their appearance" [OED], by 1923.