constant
1 Americanadjective
-
not changing or varying; uniform; regular; invariable.
All conditions during the three experiments were constant.
- Antonyms:
- changeable
-
continuing without pause or letup; unceasing.
constant noise.
- Synonyms:
- unremitting, perpetual
- Antonyms:
- fitful
-
regularly recurrent; continual; persistent.
He found it impossible to work with constant interruption.
- Antonyms:
- sporadic
-
faithful; unswerving in love, devotion, etc..
a constant lover.
- Antonyms:
- unreliable
-
steadfast; firm in mind or purpose; resolute.
- Synonyms:
- steady
-
Obsolete. certain; confident.
noun
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constants
plural
-
something that does not or cannot change or vary.
-
Physics. a number expressing a property, quantity, or relation that remains unchanged under specified conditions.
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Mathematics. a quantity assumed to be unchanged throughout a given discussion.
noun
-
Paul Henri Benjamin Balluat Paul d'Estournelles de Constant.
-
Jean Joseph Benjamin 1845–1902, French painter.
adjective
-
fixed and invariable; unchanging
-
continual or continuous; incessant
constant interruptions
-
resolute in mind, purpose, or affection; loyal
noun
-
something that is permanent or unchanging
-
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
-
-
See logical constant
noun
-
A quantity that is unknown but assumed to have a fixed value in a specified mathematical context.
-
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.
Synonym Usage
See faithful.
Other Word Forms
Derived Forms
-
nonconstantnoun
-
overconstantnessnoun
-
overconstantadjective
-
quasi-constantadjective
-
unconstantadjective
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constantlyadverb
Inflected Forms
Nouns
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.
Vocabulary lists containing constant
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
It’s so intentionally inclusive and ambitious that it turns right back around to feel limiting, pigeonholing Maddie into a place where she feels in constant competition with her colleagues and herself.
From Salon ● Aug. 8, 2026
Any talk of changing the rules, salary cap or otherwise, to put reins on this kind of success would propagate underperformance and penalize this fascinating culture of constant improvement.
From Los Angeles Times ● Aug. 8, 2026
Official police figures in Greece would confirm very few details but there was a constant drip of information from the police union who did not seem to follow the same rules as their bosses.
From BBC ● Aug. 7, 2026
Looking ahead, Krispy Kreme reiterated its forecast for systemwide sales growth of 2% to 4% in constant currency this year.
From The Wall Street Journal ● Aug. 6, 2026
I’m not sure what’s up with Crick’s constant questions, but it’s obvious there’s more going on than they’re sharing.
From "The Last Cuentista" by Donna Barba Higuera
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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
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
And so today, my fever has broken and I am still in my body, still aboard the Susan Constant, bound for the New World.
From "Blood on the River" by Elisa Carbone
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Phone-induced distractedness, flusteredness, and agitation had been constants in life before prison.
From The Wall Street Journal ● Aug. 5, 2026
Their work suggests that the Universe's fundamental constants sit within an extremely narrow range that allows liquids to flow in ways living cells depend on.
From Science Daily ● May 8, 2026
The constants not only appear compatible with a universe full of matter, but also with biological systems that depend on delicate liquid dynamics.
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
Through most of his moves, Door had been one of the few constants in his life.
From "Boy 2.0" by Tracey Baptiste
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.