white tie and tails vs tailcoat

white tie and tails and tailcoat both are nouns.

Word	Noun	Adjective	Verb	Adverb
white tie and tails	Yes	No	No	No
tailcoat	Yes	No	No	No

As nouns, white tie and tails and tailcoat are synonyms defined as:

white tie and tails and tailcoat: formalwear consisting of full evening dress for men

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

white tie and tails (noun)	tailcoat (noun)
formalwear consisting of full evening dress for men	formalwear consisting of full evening dress for men