Word.ws English Dictionary

half-lives

half-lives is the plural of half-life.

Meaning of half-life

Noun

half-life (plural half-lives)

  1. (nuclear physics) The time required for half the nuclei in a sample of an isotope to undergo radioactive decay.
    • "The guy that just left—what's he got in his lungs?" / "Well, I'm not very sure. But the two best candidates are uranium-233 and plutonium-239, one or both." / "They're in his bones too, aren't they?" / "Yeah, they're both boneseekers. And they've got half-lives of one hundred sixty-two thousand...1985, Michael Swanwick, “Boneseeker”, in In the Drift (New Ace Science Fiction Specials; series 3), New York, N.Y.: Ace Science Fiction Books, →ISBN; republished New York, N.Y.: Dover Publications...
  2. (physical) In a chemical reaction, the time required for the concentration of a reactant to fall from a chosen value to half that value.
  3. The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacological, physiologic, or radiological activity.
    • For nonporous surfaces such as steel, in a dark and low-humidity environment, the CCP virus has an 18-hour half-life—the time required for it to decrease by half , according to the researchers' findings.2020, Dr. Alan Pateman, China, Covid-19, World Domination, Lulu Press, Inc, →ISBN
  4. The amount of time it takes for an idea or a fashion to lose half of its influential power.
    • Most books of scholarship have surprisingly short intellectual half-lives during which they make a difference"1991, Robert Ackerman, Introduction to Jane Ellen Harrison's Prolegomena to the Study of Greek Religion (1903)

Questions about half-lives

What is half-lives the plural of?
Half-lives is the plural of half-life.

Words near half-lives in the dictionary

  1. half-lengths
  2. half-life
  3. half-light
  4. half-line
  5. half-lines
  6. half-lives
  7. half-long
  8. half-long vowel
  9. half-long vowels
  10. half-longs
  11. half-marathon

Source and license

Adapted from Wiktionary: half-lives (page history and authors); half-life (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.

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