adjective

- having or forming a boundary or barrier: He was blocked by a closed door. The house had a closed porch.
- brought to a close; concluded: It was a closed incident with no repercussions.
- not public; restricted; exclusive: a closed meeting; a closed bid at a private auction.
- not open to new ideas or arguments.
- self-contained; independent or self-sufficient: a closed, symbiotic relationship.
- Phonetics. (of a syllable) ending with a consonant or a consonant cluster, as has, hasp.Compare open(def 35b).
- Linguistics. (of a class of items) limited in membership and not readily expanded to include new items, as the class of inflectional affixes, articles, pronouns, or auxiliaries (opposed to open).
- Hunting, Angling. restricted as to the kind of game that may be legally taken and as to where or when it may be taken: woods closed to deer hunters.
- Mathematics.
- (of a set in which a combining operation between members of the set is defined) such that performing the operation between members of the set produces a member of the set, as multiplication in the set of integers.
- (of an interval) containing both of its endpoints.
- (of a map from one topological space to another) having the property that the image of a closed set is a closed set.
- (of a curve) not having endpoints; enclosing an area.
- (of a surface) enclosing a volume.
- (of a function or operator) having as its graph a closed set.

adjective

- blocked against entry; shut
- restricted; exclusive
- not open to question or debate
- (of a hunting season, etc) close
- maths
- (of a curve or surface) completely enclosing an area or volume
- (of a set) having members that can be produced by a specific operation on other members of the same setthe integers are a closed set under multiplication

- Also: checked phonetics
- denoting a syllable that ends in a consonant
- another word for close 1 (def. 21)

- not open to public entry or membershipthe closed society of publishing

adj.c.1200, past participle adjective from close (v.). Closed circuit is attested from 1827; closed shop in union sense from 1904; closed system first recorded 1896 in William James.