tandem vs tandem bicycle

tandem and tandem bicycle both are nouns.

Word	Noun	Adjective	Verb	Adverb
tandem	Yes	No	No	Yes
tandem bicycle	Yes	No	No	No

As nouns, tandem and tandem bicycle are synonyms defined as:

tandem and tandem bicycle: a bicycle with two sets of pedals and two seats

Other synonyms of tandem include bicycle-built-for-two.

tandem (noun)	tandem bicycle (noun)
a bicycle with two sets of pedals and two seats	a bicycle with two sets of pedals and two seats
an arrangement of two or more objects or persons one behind another

tandem (adverb)	tandem bicycle (adverb)
one behind the other