half life

1. 1.

   the time required for something to fall to half its initial value (in particular, the time for half the atoms in a radioactive substance to disintegrate)

   Synonymshalf-life

   Broadertime period

Questions about half life

What does half life mean?

half life means "the time required for something to fall to half its initial value (in particular, the time for half the atoms in a radioactive substance to disintegrate)".

What is another word for half life?

Close synonyms include half-life. Each sense on this page lists its own synonyms, because a word with several meanings rarely has one substitute that works for all of them.

Is half life a common word?

half life is banded "Uncommon" — turns up in careful writing rather than conversation. The band comes from how often the word appears in a large corpus of everyday English, not from an editor's impression.