constant

comparative more constant · superlative most constant

1. Unchanged through time or space; permanent.

   Synonyms: nonchanging

2. Consistently recurring over time; persistent.

   The constant pinging of electronic devices is driving many people to the end of their tether. Electronic devices not only overload the senses and invade leisure time. They feed on themselves: the more people tweet the more they are rewarded with followers and retweets.

   2013 November 16, Schumpeter, “The mindfulness business”, in The Economist, volume 409, number 8862

   Synonyms: amaranthine, solid, ceaseless, continual, continuate, continuous, dreich, endless

3. Steady in purpose, action, feeling, etc.

   I am constant to my purposes.

   c. 1599–1602 (date written), William Shakespeare, “The Tragedie of Hamlet, Prince of Denmarke”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act V, scene ii]

   2 more examples

   Both loving one fair maid, they yet remained constant friends.

   The New Arcadia

   c. 1580 (date written), Philippe Sidnei [i.e., Philip Sidney], “[The Second Booke] Chapter 3”, in [Fulke Greville; Matthew Gwinne; John Florio], editors, The Countesse of Pembrokes Arcadia [The New Arcadia], London: […] [John Windet] for William Ponsonbie, published 1590, →OCLC, folio 162, recto

   His gifts, his constant courtship, nothing gained.

   1700, [John] Dryden, “Theodore and Honoria, from Boccace”, in Fables Ancient and Modern; […], London: […] Jacob Tonson, […], →OCLC

4. Firm; solid; not fluid.

   If […] you mix them, you may turn these two fluid liquors into a constant body.

   1659 December 30 (date written), Robert Boyle, New Experiments Physico-Mechanicall, Touching the Spring of the Air, and Its Effects […], Oxford, Oxfordshire: […] H[enry] Hall, printer to the University, for Tho[mas] Robinson, published 1660, →OCLC

5. obsoleteConsistent; logical.

   I am no more mad than you are: make the trial of it with any constant question.

   c. 1601–1602 (date written), William Shakespeare, “Twelfe Night, or What You Will”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act IV, scene ii]

6. complexity theorycomputingBounded above by a constant.

   constant time   constant space

plural constants

1. That which is permanent or invariable.
2. algebraA quantity that remains at a fixed value throughout a given discussion or operation.

   We also establish that constants are local extremizers of the Tomas-Stein adjoint restriction inequality as well as of another inequality appearing in the program..

   2015, Emanuel Carneiro, Damiano Foschi, Diogo Oliveira e Silva, Christoph Thiele, “A sharp trilinear inequality related to Fourier restriction on the circle”, in arXiv

   Antonyms: variable

3. sciencesAny property of an experiment, determined numerically, that does not change under given circumstances.

   Based on their acid dissociation constants (pKa), seleneous^([sic]) acid (H2SeO3) and selenic acid (H2SeO4) are anionic under common environmental conditions [48], e.g., as selenite (SeO32−) and selenate (SeO42−).

   2015, Lenny H.E. Winkel et al., “Selenium Cycling Across Soil-Plant-Atmosphere Interfaces: A Critical Review”, in Nutrients, volume 7, →DOI

4. computingAn identifier that is bound to an invariant value; a fixed value given a name to aid in readability of source code.

1. rareA male given name from Latin, feminine equivalent Constance.
2. A surname.
3. A populated place in Saint George parish, Barbados.