floating bridge vs pontoon bridge

floating bridge and pontoon bridge both are nouns.

Word	Noun	Adjective	Verb	Adverb
floating bridge	Yes	No	No	No
pontoon bridge	Yes	No	No	No

As nouns, floating bridge and pontoon bridge are synonyms defined as:

floating bridge and pontoon bridge: a temporary bridge built over a series of pontoons

Other synonyms of floating bridge include bateau bridge.

floating bridge (noun)	pontoon bridge (noun)
a temporary bridge built over a series of pontoons	a temporary bridge built over a series of pontoons