constant
Noun pluralconstants
Pluralconstants
- 1Occurring repeatedly and persistently over a period of time.
The constant interruptions made it hard to finish the report.
Living near the airport means putting up with constant aircraft noise.
Similarcontinuous, persistent, endless, continual, nonstop
Oppositeintermittent, occasional, sporadic
Note
Here the sameness lies in repetition, not in a steady level. The Economist wrote in 2013 of "the constant pinging of electronic devices": each ping stops, but another always follows. Compare the "unchanged" meaning. A constant temperature never moves, while constant interruptions keep happening. Context usually decides between them, because nouns for sounds and events pull toward this reading.
Checked 7 Nov 2026 · 2 facts
- The Economist used the quoted wording in 2013, in “The mindfulness business”. en.wiktionary.org
- The quoted phrase accurately reproduces the wording attributed to The Economist. en.wiktionary.org
- 2Remaining unchanged through time or across space; permanent.
The machine maintains a constant pressure throughout the process.
At this depth, the ocean temperature is nearly constant.
UsageOften at a constant speed or rate, or after stay or remain: the temperature stays constant.
Similarsteady, stable, fixed, unchanging, uniform
Oppositevariable, fluctuating, inconstant, irregular
- 3In mathematics and science, a quantity or value that stays fixed throughout a calculation, discussion, or experiment.
The speed of light appears as a constant in many physics equations.
When solving for x, treat the other terms as constants.
Note
Algebra's counterpart to the variable: within one problem, a constant holds a single value while a variable is free to change. Which is which depends on the discussion rather than on the symbol. When you solve for x, the other letters are treated as constants, even though in another problem they might be the unknowns.
Checked 7 Nov 2026 · 3 facts
- A constant stays fixed while a variable may change. openstax.org
- Whether a symbol represents a constant or a variable depends on its intended role. patthompson.net
- Fixed parameters can be treated as constants when solving for x, and can be unknowns in another problem. Other terms containing x, such as 2x or x², are not constants. openstax.org
- 4Something that stays permanent or unchanging amid surrounding change.
Amid the chaos of the newsroom, his calm was the one constant.
Their friendship was a constant through decades of upheaval.
- 5Steady and faithful in purpose, action, or feeling.
A constant ally, she never wavered in her backing for the cause.
He remained constant in his devotion despite years of separation.
UsageOften constant to a person or purpose, or constant in a feeling: constant in his devotion.
Similarfaithful, loyal, steadfast, devoted, true
Oppositefickle, inconstant, unfaithful, disloyal
Note
Shakespeare's Hamlet says, "I am constant to my purposes." Philip Sidney writes of two men who love one woman yet "remained constant friends," and Dryden of a suitor whose "constant courtship" gained nothing.
I am constant to my purposes.
Both loving one fair maid, they yet remained constant friends.
Less common meanings
- 6A named identifier bound to a value that cannot change, used to make source code more readable.
Defining the maximum size as a constant prevents accidental changes later.
Good programmers give each constant a clear, descriptive name.
Oppositevariable
Note
Programmers declare a constant to give a fixed value a meaningful name, such as a maximum size, instead of scattering a bare number through the code. Once bound, the name cannot be reassigned, which guards against accidental changes. That protection separates it from a variable, whose value the program may update. Readability is the other half of the point.
Checked 7 Nov 2026 · 3 facts
- Named constants replace repeated bare values with meaningful names, improving readability. doc.rust-lang.org
- A constant's binding prevents reassignment, guarding against accidental reassignment. developer.mozilla.org
- A variable may be reassigned during execution. developer.mozilla.org
- 7Firm and solid in form; not fluid.
Note
Of all the senses, this one stays closest to the Latin "stand firm" behind the "unchanged" meaning. A constant body holds its shape instead of flowing. Robert Boyle could still write about 1660 of turning "two fluid liquors into a constant body." Present-day English no longer uses constant this way. Firm and solid do this work now, so treat the sense as obsolete.
Checked 7 Nov 2026 · 4 facts
- Constant derives ultimately from Latin cōnstāre, meaning “to stand firm.” en.wiktionary.org
- Constant historically meant solid rather than fluid. en.wiktionary.org
- Robert Boyle used the quoted wording. en.wiktionary.org
- Under the requested publication-date convention, use 1660, when New Experiments Physico-Mechanicall first appeared. Wiktionary identifies 1659 as its writing date. boyle.bbk.ac.uk
- 8Consistent and free from contradiction; logical.
I am no more mad than you are: make the trial of it with any constant question.
c. 1601, William Shakespeare, “Twelfe Night, or What You Will”Note
A modern reader meets this meaning only in older texts, where a constant question is a coherent, logical one. In Shakespeare's Twelfth Night, a speaker protesting his sanity says, "make the trial of it in any constant question," meaning test me with any reasonable question. The sense is obsolete. In your own writing, use consistent or coherent instead.
Checked 7 Nov 2026 · 2 facts
- The historical meaning of constant was consistent or logical. en.wiktionary.org
- In Shakespeare’s Twelfth Night, a character protesting his sanity says the quoted words; the speaker is Malvolio. gutenberg.org
- 9Bounded above by a fixed value; not growing with the size of the input.
Showing meanings only.
Practice
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Origin
Latin cōnstāre meaning "to stand firm" gave constans (accusative constantem), which passed through Old French constant into Middle English constant. It took the place of singal, the native Old English word.