gangway vs overcrossing

gangway and overcrossing both are nouns.

Word	Noun	Adjective	Verb	Adverb
gangway	Yes	No	No	No
overcrossing	Yes	No	No	No

As nouns, overcrossing is a hypernym of gangway; that is, overcrossing is a word with a broader meaning than gangway:

Other hypernyms of gangway include footbridge, pedestrian bridge.

gangway (noun)	overcrossing (noun)
a temporary passageway of planks (as over mud on a building site)	a bridge designed for pedestrians
a temporary bridge for getting on and off a vessel at dockside
passageway between seating areas as in an auditorium or passenger vehicle or between areas of shelves of goods as in stores