racing circuit vs racecourse

racing circuit and racecourse both are nouns.

Word	Noun	Adjective	Verb	Adverb
racing circuit	Yes	No	No	No
racecourse	Yes	No	No	No

As nouns, racecourse is a hypernym of racing circuit; that is, racecourse is a word with a broader meaning than racing circuit:

Other hypernyms of racing circuit include racetrack, raceway, track.

racing circuit (noun)	racecourse (noun)
a racetrack for automobile races	a course over which races are run