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• constant
  constant

  adjective

  not changing or varying; uniform; regular; invariable.
• Constant
  Constant

  noun

  Paul Henri Benjamin Balluat Paul d'Estournelles de Constant.

constant

¹ American  

[kon-stuhnt] / ˈkɒn stənt /

adjective

1. not changing or varying; uniform; regular; invariable.

   All conditions during the three experiments were constant.

   Synonyms:

   permanent, immutable

   Antonyms:

   changeable

2. continuing without pause or letup; unceasing.

   constant noise.

   Synonyms:

   unremitting, perpetual

   Antonyms:

   fitful

3. regularly recurrent; continual; persistent.

   He found it impossible to work with constant interruption.

   Synonyms:

   ceaseless, incessant

   Antonyms:

   sporadic

4. faithful; unswerving in love, devotion, etc..

   a constant lover.

   Synonyms:

   true, staunch, loyal

   Antonyms:

   unreliable

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

   Synonyms:

   steady

6. Obsolete. certain; confident.

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noun

• constants
  plural

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.

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

Constant ² American  

[kawn-stahn] / kɔ̃ˈstɑ̃ /

noun

1. Paul Henri Benjamin Balluat Paul d'Estournelles de Constant.

2. Jean Joseph Benjamin 1845–1902, French painter.

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Constant ¹ British  

/ kɔ̃stɑ̃ /

noun

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

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constant ² British  

/ ˈkɒnstənt /

adjective

1. fixed and invariable; unchanging

2. continual or continuous; incessant

   constant interruptions

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

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noun

1. something that is permanent or unchanging

2. a specific quantity that is always invariable

   the velocity of light is a constant

3. 1. maths a symbol representing an unspecified number that remains invariable throughout a particular series of operations

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

4. See logical constant

constant Scientific  

/ kŏn′stənt /

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.

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constant Cultural  

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

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Synonym Usage

See faithful.

Other Word Forms

Derived Forms

• nonconstant
  noun
• overconstantness
  noun
• overconstant
  adjective
• quasi-constant
  adjective
• unconstant
  adjective
• constantly
  adverb

Inflected Forms

Nouns

• constants
  plural

Etymology

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

Explanation

Think of something or someone that does not change as constant. A classmate's constant drumming on the table with his fingers could be a constant source of annoyance. Constant derives from Latin verb meaning "to stand with," so something constant is continually standing with you and not wavering. You may be thankful for the constant companionship of your dog but not necessarily for your teacher's constant homework assignments. In math and science, a constant is a number that is fixed and known, unlike a variable which changes with the context. That idea crosses over to real life. If a friend is a constant in your life, that means they have always been with you and there for you.

Example Sentences

See Examples For:

constant Constant constants

But he said the constant public scrutiny she faced may not have allowed her room to address her mental health in private.

From BBC ● Aug. 21, 2026

The concept is simple: design your home to keep the temperature constant at all times, by effectively sealing it against the elements.

From BBC ● Aug. 21, 2026

The central bank also released a constant stream of forward guidance hinting at low rates in the future to deter markets from bidding up yields.

From The Wall Street Journal ● Aug. 20, 2026

Yet his attitude of constant haggling over everything that isn’t nailed down, and some things that were supposed to be, isn’t helpful.

From The Wall Street Journal ● Aug. 19, 2026

His parents' constant badgering was starting to irritate him, and he told them he didn't want to talk about it anymore.

From Nazi Saboteurs by Samantha Seiple

Constant, standing on a striped rock, consists of two color patches; the rest is largely blue sea, topped by a light-gray strip of sky.

From The Wall Street Journal ● Aug. 1, 2026

Constant nibbling of more than 200 species of plants means riverbanks thrive and their water front burrows improve soils.

From BBC ● Jun. 30, 2026

Constant stretching and compression of a moon can create recurring wet dry cycles where water repeatedly evaporates and condenses.

From Science Daily ● May 29, 2026

Constant improvements in semiconductor technology could see other new classes of chips rise up and take their place, OneChronos CEO Kelly Littlepage said in comments shared with MarketWatch.

From MarketWatch ● May 12, 2026

Constant vacancies were necessary in case an agent needed emergency lodging.

From "City Spies" by James Ponti

Phone-induced distractedness, flusteredness, and agitation had been constants in life before prison.

From The Wall Street Journal ● Aug. 5, 2026

The idea remains highly theoretical, and many physicists would caution that there is still no accepted explanation for why the constants of nature have their observed values.

From Science Daily ● May 8, 2026

Spurs' 5-3-2 shape lacks coverage in the wide areas with the wing-backs the only constants here.

From BBC ● Mar. 12, 2026

The only constants are her signature hat toss and those solo lakeside walks, part of a montage illustrating her perpetual forward movement.

From Salon ● Jan. 31, 2026

And in this report I do not fool myself into thinking I am dealing with constants.

From "Travels with Charley in Search of America" by John Steinbeck

Related Words

• ceaseless
• chronic
• continual
• continuous
• endless
• eternal
• incessant
• nonstop
• perpetual
• persistent
• relentless
• sustained
• unending
• uninterrupted
• unrelenting
• unremitting