door

(noun) a swinging or sliding barrier that will close the entrance to a room or building or vehicle. Examples: "He knocked on the door." "He slammed the door as he left."

(noun) the entrance (the space in a wall) through which you enter or leave a room or building; the space that a door can close. Synonyms: doorway, room access, threshold. Example: "He stuck his head in the doorway."

(noun) anything providing a means of access (or escape). Examples: "We closed the door to haitian immigrants." "Education is the door to success."

(noun) a structure where people live or work (usually ordered along a street or road). Examples: "The office next door." "They live two doors up the street from us."

(noun) a room that is entered via a door. Example: "His office is the third door down the hall on the left."