Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “half-life”

See all translations

half-life

noun [C] uk   /ˈhɑːf.laɪf/ us    /ˈhæf-/ specialized
the length of time needed for the radioactivity of a radioactive substance to be reduced by half
Translations of “half-life”
in Chinese (Traditional) (放射性物質的)半衰期…
in Chinese (Simplified) (放射性物质的)半衰期…
(Definition of half-life from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
What is the pronunciation of half-life?
Add Cambridge dictionaries to your browser to your website

Definitions of “half-life” in other dictionaries

Word of the Day

escapism

a way of avoiding an unpleasant or boring life, especially by thinking, reading, etc. about more exciting but impossible activities

Word of the Day

Lies, lies, lies!

by Kate Woodford,
February 25, 2015
​​​ According to sociologists (=people who study the relationships between people living in groups), we are good at lying. As a species, we have developed a remarkable ability to deceive each other (= persuade each other that something false is true). Being able to say things that are not true can help with

Read More 

showrooming noun

February 23, 2015
the activity of examining a product in a physical store and then making the purchase with an online retailer Amazon’s new smartphone is specifically designed to make showrooming fast and easy.

Read More