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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

After all, his previous four seasons spent coaching the Trojans had been nothing short of a powder keg, filled with ups and downs, as well as a constant undercurrent of tension and uncertainty.

From Los Angeles Times ● Jul. 28, 2026

For the second quarter, GSK reported turnover of 8.41 billion pounds, up 5% at constant currency, and core operating profit of 2.8 billion pounds, up 7% excluding currency movements.

From The Wall Street Journal ● Jul. 28, 2026

Britain's backing of Ukraine has been constant since Russia's invasion four years ago, and the UK has committed £25bn in funding, external for the country's war fight.

From BBC ● Jul. 26, 2026

He was worn out from not being able to sleep due to the "constant noise."

From Barron's ● Jul. 25, 2026

With fewer birds to eat the insects, their population exploded, and the sweet sound of birdsong was replaced with the constant buzzing of scaly little wings.

From "The Wild Robot Protects" by Peter Brown

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

From BBC ● Jun. 30, 2026

Social media has created the conditions for this “doomer mindset” to flourish: Constant exposure to information, algorithm-driven echo chambers, and excessive screen time distort perception and isolate teens, making it harder to discern what’s true.

From Slate ● May 12, 2026

Constant sprinting also risks crowding out time for quiet reflection.

From The Wall Street Journal ● Jan. 8, 2026

Constant airflow can also lead to dry eyes and skin, making long-term use uncomfortable.

From Science Daily ● Nov. 21, 2025

The Susan Constant turns, sailors rush to pull on lines, and we are on our way, gliding in to shore.

From "Blood on the River" by Elisa Carbone

For decades, the mystery of fundamental constants was mostly explored through black holes, stars, and subatomic particles.

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

"Today, the kilogram is defined on the basis of fundamental constants using an electromechanical device that compares electric current to mass," St-Jean explained.

From Science Daily ● Mar. 1, 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

The others would come and go, but Cassandra and I were constants.

From "Ugly" by Robert Hoge

Related Words

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