flybridge vs fly bridge

flybridge and fly bridge both are nouns.

Word	Noun	Adjective	Verb	Adverb
flybridge	Yes	No	No	No
fly bridge	Yes	No	No	No

As nouns, flybridge and fly bridge are synonyms defined as:

flybridge and fly bridge: the highest navigational bridge on a ship; a small (often open) deck above the pilot house

Other synonyms of flybridge include flying bridge, monkey bridge.

flybridge (noun)	fly bridge (noun)
the highest navigational bridge on a ship; a small (often open) deck above the pilot house	the highest navigational bridge on a ship; a small (often open) deck above the pilot house