club sandwich vs triple-decker

club sandwich and triple-decker both are nouns.

Word	Noun	Adjective	Verb	Adverb
club sandwich	Yes	No	No	No
triple-decker	Yes	No	No	No

As nouns, club sandwich and triple-decker are synonyms defined as:

club sandwich and triple-decker: made with three slices of usually toasted bread

Other synonyms of club sandwich include three-decker.

club sandwich (noun)	triple-decker (noun)
made with three slices of usually toasted bread	made with three slices of usually toasted bread