[ kon-stuhnt ]
See synonyms for constant on
  1. not changing or varying; uniform; regular; invariable: All conditions during the three experiments were constant.

  2. continuing without pause or letup; unceasing: constant noise.

  1. regularly recurrent; continual; persistent: He found it impossible to work with constant interruption.

  2. faithful; unswerving in love, devotion, etc.: a constant lover.

  3. steadfast; firm in mind or purpose; resolute.

  4. Obsolete. certain; confident.

  1. something that does not or cannot change or vary.

  2. Physics. a number expressing a property, quantity, or relation that remains unchanged under specified conditions.

  1. Mathematics. a quantity assumed to be unchanged throughout a given discussion.

Origin of constant

First recorded in 1350–1400; Middle English, from Latin constant- (stem of constāns, present participle of constāre “to stand firm”), equivalent to con- con- + stā- stand + -nt- present participle suffix

synonym study For constant

4. See faithful.

Other words for constant

Opposites for constant

Other words from constant

  • con·stant·ly, adverb
  • non·con·stant, noun, adjective
  • o·ver·con·stant, adjective
  • o·ver·con·stant·ness, noun
  • qua·si-con·stant, adjective
  • un·con·stant, adjective

Words Nearby constant

Other definitions for Constant (2 of 2)

[ kawn-stahn ]

  1. Paul Hen·ri Ben·ja·min Bal·luat [pawl ahn-reeban-zha-manba-lwa]. /pɔl ɑ̃ˈri bɛ̃ ʒaˈmɛ̃ baˈlwa/. Paul d'Estournelles de Constant.

  2. Jean Jo·seph Ben·ja·min [zhahnzhaw-zefban-zha-man], /ʒɑ̃ ʒɔˈzɛf bɛ̃ ʒaˈmɛ̃/, 1845–1902, French painter. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use constant in a sentence

British Dictionary definitions for constant (1 of 2)


/ (ˈkɒnstənt) /

  1. fixed and invariable; unchanging

  2. continual or continuous; incessant: constant interruptions

  1. resolute in mind, purpose, or affection; loyal

  1. something that is permanent or unchanging

  2. a specific quantity that is always invariable: the velocity of light is a constant

    • maths a symbol representing an unspecified number that remains invariable throughout a particular series of operations

    • physics a theoretical or experimental quantity or property that is considered invariable throughout a particular series of calculations or experiments

Origin of constant

C14: from Old French, from Latin constāns standing firm, from constāre to be steadfast, from stāre to stand

Derived forms of constant

  • constantly, adverb

British Dictionary definitions for Constant (2 of 2)


/ (French kɔ̃stɑ̃) /

  1. Benjamin (bɛ̃ʒamɛ̃). real name Henri Benjamin Constant de Rebecque. 1767–1830, French writer and politician: author of the psychological novel Adolphe (1816)

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for constant


[ kŏnstənt ]

  1. A quantity that is unknown but assumed to have a fixed value in a specified mathematical context.

  2. A theoretical or experimental quantity, condition, or factor that does not vary in specified circumstances. Avogadro's number and Planck's constant are examples of constants.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Cultural definitions for constant


A number that appears in equations and formulas and does not vary or change. Examples are Planck's constant and the speed of light.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.