1
a
: not open
b
: enclosed
c
: composed entirely of closed tubes or vessels
a closed circulatory system
2
a
: having the skin intact with no underlying tissue exposed
closed wounds
see also closed fracture
b
of a head injury
: having the skull intact : not marked by fracture or penetration of the skull
3
a
: forming a self-contained unit allowing no additions
closed association
b(1)
: traced by a moving point that returns to an arbitrary starting point
closed curve
also
: so formed that every plane section is a closed curve
closed surface
(2)
: characterized by mathematical elements that when subjected to an operation produce only elements of the same set
the set of whole numbers is closed under addition and multiplication
(3)
: containing all the limit points of every possible subset
a closed interval contains its endpoints
c
: characterized by continuous return and reuse of the working substance
a closed cooling system
d
of a racecourse
: having the same starting and finishing point
4
a
: confined to a few
closed membership
b
: excluding participation of outsiders or witnesses : conducted in strict secrecy
c
: rigidly excluding outside influence
a closed mind
5
: ending in a consonant
closed syllable
closed
2 of 2past tense and past participle of close entry 1
Cite this Entry
“Closed.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/closed. Accessed 1 Sep. 2026.
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