coverall vs dust coat

coverall and dust coat both are nouns.

Word	Noun	Adjective	Verb	Adverb
coverall	Yes	No	No	No
dust coat	Yes	No	No	No

As nouns, dust coat is a hyponym of coverall; that is, dust coat is a word with a more specific, narrower meaning than coverall:

coverall: a loose-fitting protective garment that is worn over other clothing
dust coat: a loose coverall (coat or frock) reaching down to the ankles

Other hyponyms of coverall include duster, gabardine, gaberdine, smock, jumper, boilers suit, boilersuit, overall.

coverall (noun)	dust coat (noun)
a loose-fitting protective garment that is worn over other clothing	a loose coverall (coat or frock) reaching down to the ankles