dress suit vs tail coat

dress suit and tail coat both are nouns.

Word	Noun	Adjective	Verb	Adverb
dress suit	Yes	No	No	No
tail coat	Yes	No	No	No

As nouns, dress suit and tail coat are synonyms defined as:

dress suit and tail coat: formalwear consisting of full evening dress for men

Other synonyms of dress suit include full dress, tailcoat, tails, white tie, white tie and tails.

dress suit (noun)	tail coat (noun)
formalwear consisting of full evening dress for men	formalwear consisting of full evening dress for men