Door

n. barrier of wood or other material which can be opened and closed; doorway, opening through which one enters

v. strike a passing person or cyclist by unexpectedly opening a car door (Slang); serve as a doorman/doorwoman of a building or nightclub

A door is a panel or barrier, usually hinged, sliding, or electronic, that is used to cover an opening in a wall or partition going into a building or space. A door can be opened to give access and closed more or less securely. The term door is also applied to the opening itself, more properly known as the doorway.
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Noun
1. a swinging or sliding barrier that will close the entrance to a room or building or vehicle; "he knocked on the door"; "he slammed the door as he left"
(hypernym) movable barrier
(hyponym) car door
(part-holonym) doorway, room access, threshold
(part-meronym) lock
2. 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"
(synonym) doorway, room access, threshold
(hypernym) entrance, entranceway, entryway, entry, entree
(hyponym) exterior door, outside door
(part-holonym) wall
(part-meronym) casing, case
3. anything providing a means of access (or escape); "we closed the door to Haitian immigrants"; "education is the door to success"
(hypernym) entree, access, accession, admittance
(hyponym) open door
4. a structure where people live or work (usually ordered along a street or road); "the office next door"; "they live two doors up the street from us"
(hypernym) structure, construction
5. a room that is entered via a door; "his office is the third door down the hall on the left"
(hypernym) room

prep. through, along, by

adj. through

(n.)
The frame or barrier of boards, or other material, usually turning on hinges, by which an entrance way into a house or apartment is closed and opened.
  

(n.)
Passage; means of approach or access.
  

(n.)
An opening in the wall of a house or of an apartment, by which to go in and out; an entrance way.
  

(n.)
An entrance way, but taken in the sense of the house or apartment to which it leads.