adjective \ ˈklōzd \
|Updated on: 7 Jul 2018

Definition of closed

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

  1. He looked at me through half-closed eyes.

  2. The store is closed for lunch between 1 and 2 p.m.

  3. The beach is closed this time of night.

  4. These restrooms are closed for cleaning.

  5. The chairman declared the discussion closed and allowed no further speeches.

Recent Examples of closed from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'closed.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of closed

13th century

in the meaning defined at sense 1a

See Words from the same year
NEW! Time Traveler

CLOSED Defined for English Language Learners


Definition of closed for English Language Learners

  • : covering an opening : having an opening that is covered

  • : not operating or open to the public

  • : having ended : not being worked on anymore

CLOSED Defined for Kids


adjective \ ˈklōzd \

Definition of closed for Students

: not open
  • a closed door

Medical Dictionary


adjective \ ˈklōzd \

medical Definition of closed

1 : being a complete self-contained system with nothing transferred in or out
  • a closed thermodynamic system
2 a : covered by unbroken skin
  • a closed fracture
b : not penetrating 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 SheaNational GeographicDecember 2006
3 : not discharging pathogenic organisms to the outside
  • a case of closed tuberculosis
— compare open 2

Law Dictionary



legal Definition of closed

1 : confined to a few
  • closed membership
2 : excluding outsiders or witnesses : conducted in secrecy
  • closed hearings

Seen and Heard

What made you want to look up closed? Please tell us where you read or heard it (including the quote, if possible).

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!


a simultaneous discharge of guns

Get Word of the Day daily email!

Test Your Vocabulary

Obscure Shapes

  • a-pile-of-three-dimensional-shapes-in-green
  • Something that is ooid is shaped like:
Spell It

Can you spell these 10 commonly misspelled words?

Bee Cubed

Test Your Knowledge - and learn some interesting things along the way.


Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!