passageway vs gallery

passageway and gallery both are nouns.

Word	Noun	Adjective	Verb	Adverb
passageway	Yes	No	No	No
gallery	Yes	No	No	No

As nouns, gallery is a hyponym of passageway; that is, gallery is a word with a more specific, narrower meaning than passageway:

Other hyponyms of passageway include aisle, gangway, arcade, areaway, corridor, drift, heading, gangway, gate, shaft, tunnel, walk-through.

passageway (noun)	gallery (noun)
a passage between rooms or between buildings	narrow recessed balcony area along an upper floor on the interior of a building; usually marked by a colonnade
a path or channel or duct through or along which something may pass	a covered corridor (especially one extending along the wall of a building and supported with arches or columns)
	a long usually narrow room used for some specific purpose
	a room or series of rooms where works of art are exhibited
	a porch along the outside of a building (sometimes partly enclosed)
	a horizontal (or nearly horizontal) passageway in a mine
	spectators at a golf or tennis match