monkey bridge vs bridge deck

monkey bridge and bridge deck both are nouns.

Word	Noun	Adjective	Verb	Adverb
monkey bridge	Yes	No	No	No
bridge deck	Yes	No	No	No

As nouns, bridge deck is a hypernym of monkey bridge; that is, bridge deck is a word with a broader meaning than monkey bridge:

monkey bridge: the highest navigational bridge on a ship; a small (often open) deck above the pilot house
bridge deck: an upper deck where a ship is steered and the captain stands

Other hypernyms of monkey bridge include bridge.

monkey bridge (noun)	bridge deck (noun)
a high narrow platform above a deck or in an engine room or boiler room	an upper deck where a ship is steered and the captain stands
the highest navigational bridge on a ship; a small (often open) deck above the pilot house