1. Continually occurring; persistent: constant surveillance. See Synonyms at continual.
2. Regularly recurring: plagued by constant interruptions.
3. Unchanging in nature, value, or extent; invariable: a constant wind speed.
4. Steadfast in purpose, loyalty, or affection; faithful. See Synonyms at faithful.
1. Something that is unchanging or invariable.
a. A quantity assumed to have a fixed value in a specified mathematical context.
b. An experimental or theoretical condition, factor, or quantity that does not vary or that is regarded as invariant in specified circumstances.
[Middle English, from Old French, from Latin cōnstāns, cōnstant-, present participle of cōnstāre, to stand firm : com-, intensive pref.; see COM- + stāre, to stand; see stā- in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The American Heritage Dictionary Blog
Check out our blog, updated regularly, for new words and revised definitions, interesting images from the 5th edition, discussions of usage, and more.