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
Examples of closed in a Sentence
He looked at me through half-closed eyes.
The store is closed for lunch between 1 and 2 p.m.
The beach is closed this time of night.
These restrooms are closed for cleaning.
The chairman declared the discussion closed and allowed no further speeches.
Recent Examples on the Web
The system will use a closed Brayton cycle to convert heat into electricity, supported by heat pipes and a boron carbide radiation shield.
—
Mrigakshi Dixit, Interesting Engineering, 23 Apr. 2026
The Fresno County sheriff’s office issued an evacuation warning for an area on the north shore of Pine Flat Lake, and a section of Trimmer Springs Road was closed.
—Bay Area News Group, Mercury News, 23 Apr. 2026
However, the house doesn’t host invitation-only selling exhibitions or closed auctions; all of its shows are open to the public.
—George Nelson, ARTnews.com, 23 Apr. 2026
Police said the northbound I-55 ramp to eastbound I-80 remains closed as crews work to clear the area.
—Elyssa Kaufman, CBS News, 23 Apr. 2026
See All Example Sentences for closed
Examples are automatically compiled from online sources to
show current usage.
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Mrigakshi Dixit, Interesting Engineering, 23 Apr. 2026
The Fresno County sheriff’s office issued an evacuation warning for an area on the north shore of Pine Flat Lake, and a section of Trimmer Springs Road was closed.
—Bay Area News Group, Mercury News, 23 Apr. 2026
However, the house doesn’t host invitation-only selling exhibitions or closed auctions; all of its shows are open to the public.
—George Nelson, ARTnews.com, 23 Apr. 2026
Police said the northbound I-55 ramp to eastbound I-80 remains closed as crews work to clear the area.
—Elyssa Kaufman, CBS News, 23 Apr. 2026
See All Example Sentences for closed
Cite this Entry
“Closed.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/closed. Accessed 30 Apr. 2026.
Copy CitationKids Definition
closed
adjective1
a
: not open : enclosed
b
: made up entirely of closed tubes or vessels
a closed circulatory system
2
: formed by a line that returns to its starting point
a closed curve
3
: having elements that when a mathematical operation (as addition) is performed on them produce only other elements of the same set
the set of whole numbers is closed under addition
4
: not admitting or not easily admitting new members
a closed meeting
a closed society
Medical Definition
closed
adjective1
: being a complete self-contained system with nothing transferred in or out
a closed thermodynamic system
2
a
: having the skin intact with no underlying tissue exposed
closed wounds
see closed fracture
b
of a head injury
: having the skull intact : not marked by fracture or penetration of the skull
Closed head injuries result from the force of a blast or a blow in which the skull remains intact but the brain, surrounded by fluid like an egg yolk, gets wrenched or slammed against the skull wall.—Neil Shea
Neil Shea3
: not discharging pathogenic organisms to the outside
a case of closed tuberculosis
compare open entry 1 sense 2
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