half life
/ˈhæfˌlaɪf/
noun
- The time it takes for half of the atoms in a radioactive substance to decay.
- The half-life of carbon-14 is about 5,730 years.
- Uranium-238 has a half-life of 4.5 billion years.
- Scientists use half-life to date ancient fossils and rocks.
- The time it takes for the amount or effect of something (such as a drug or chemical) to decrease by half in the body or environment.
- The half-life of caffeine in the human body is about five hours.
- Doctors consider a drug's half-life when deciding how often to give it.
- The half-life of this pesticide in soil is roughly 30 days.
- A period during which something declines or loses half of its value, popularity, or effectiveness.
- In the tech industry, the half-life of a new gadget's popularity gets shorter every year.
- The half-life of that fashion trend was surprisingly short.
- The half-life of a viral internet meme is often just a few days.