gallery has 6 distinct synonyms spread across 3 of its 7 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
spectators at a golf or tennis match
Synonyms, antonyms and the broader and narrower relations for gallery come from Princeton University’s WordNet. Full sources and licences.
a room or series of rooms where works of art are exhibited
a long usually narrow room used for some specific purpose
“shooting gallery”
a covered corridor (especially one extending along the wall of a building and supported with arches or columns)
narrow recessed balcony area along an upper floor on the interior of a building; usually marked by a colonnade
a horizontal (or nearly horizontal) passageway in a mine
“they dug a drift parallel with the vein”