MEANING
1. The time needed for the activity or undecayed radioactive material in a sample to decrease by half.
2. The time needed for the amount or concentration of a substance in the body to decrease by half.
3. The period over which something gradually loses its force, relevance, or presence in people’s memories.
Use it for
understanding a measured rate of radioactive decay; distinguishing half remaining from complete disappearance; interpreting a literal scientific use of half-lifeExpresses persistence through gradual decline: something can weaken substantially without disappearing all at once. Writing functions: Transience / Impermanence.
Words that belong together
- a radioactive half-life
- a long half-life
- the half-life of an isotope
On the page
The exhibition explained why a long half-life could leave a place dangerous for generations.
The report distinguished the isotope’s half-life from the time people had lived nearby.
The leaflet described the drug’s half-life without promising an exact time when she would feel different.
The researcher measured its half-life in the body rather than its radioactive decay.
The house had a long half-life in her dreams, losing one room each year.
Word forms
- Base
- half-life
Usage notes
Countable noun: half-life, half-lives. Established hyphenated compound Word. Literal half-lives concern a defined halving process; figurative use need not refer to an exact measured interval. Register: neutral. Commonness: moderately common; literal uses technical (dictionary-informed qualitative editorial estimate; not a measured frequency).
Practice this word in a sentenceYour margin notes
Keep a thought for later. Sign in to save privately.