constant
1 Americanadjective
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not changing or varying; uniform; regular; invariable.
All conditions during the three experiments were constant.
- Antonyms:
- changeable
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continuing without pause or letup; unceasing.
constant noise.
- Synonyms:
- unremitting, perpetual
- Antonyms:
- fitful
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regularly recurrent; continual; persistent.
He found it impossible to work with constant interruption.
- Antonyms:
- sporadic
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faithful; unswerving in love, devotion, etc..
a constant lover.
- Antonyms:
- unreliable
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steadfast; firm in mind or purpose; resolute.
- Synonyms:
- steady
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Obsolete. certain; confident.
noun
-
something that does not or cannot change or vary.
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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.
noun
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
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physics a theoretical or experimental quantity or property that is considered invariable throughout a particular series of calculations or experiments
-
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See logical constant
-
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.
Related Words
See faithful.
Other Word Forms
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.
His magisterial presence was a constant in his performances, from the time he was in his 20s into his later years.
From Los Angeles Times • May 26, 2026
For the president, the explanation for missing it ensured that even a private celebration became part of a broader public narrative shaped by governance, conflict, and constant media attention.
From Salon • May 23, 2026
Faced with the Russian onslaught, Ukraine’s defense companies have also mastered the art of manufacturing cheap products in vast quantities, as constant feedback from front-line units improves performance and counters Russian innovation.
From The Wall Street Journal • May 23, 2026
"We spend our days shut in, alone with our thoughts, our problems, and the constant worry about what's going to happen to us."
From BBC • May 22, 2026
Her constant prattle had given way to a dreamier state.
From "The Long-Lost Home" by Maryrose Wood
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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.