sport coat vs sports coat

sport coat and sports coat both are nouns.

Word	Noun	Adjective	Verb	Adverb
sport coat	Yes	No	No	No
sports coat	Yes	No	No	No

As nouns, sport coat and sports coat are synonyms defined as:

sport coat and sports coat: lightweight single-breasted jacket; often striped in the colors of a club or school

Other synonyms of sport coat include blazer, sport jacket, sports jacket.

sport coat (noun)	sports coat (noun)
lightweight single-breasted jacket; often striped in the colors of a club or school	lightweight single-breasted jacket; often striped in the colors of a club or school