adj. 1. Not changing or varying; continuous: a constant gentle rain; drove at a constant speed. 2. Happening regularly or repeatedly; continual: the constant barking of the dog next door; constant interruptions. See Synonyms at continual. 3. Unchanging in nature, value, or extent; invariable: a constant wind speed. 4. Steadfast in purpose, loyalty, or affection; faithful: a constant friend. See Synonyms at faithful. n. 1. Something that is unchanging or invariable. 2. 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.] constant·ly adv. |
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