door has 3 distinct synonyms spread across 1 of its 5 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.
a swinging or sliding barrier that will close the entrance to a room or building or vehicle
“he knocked on the door”
Synonyms, antonyms and the broader and narrower relations for door come from Princeton University’s WordNet. Full sources and licences.
the entrance (the space in a wall) through which you enter or leave a room or building; the space that a door can close
“he stuck his head in the doorway”
a structure where people live or work (usually ordered along a street or road)
“the office next door”
a room that is entered via a door
“his office is the third door down the hall on the left”