Half-life (noun)

The time taken for half the atoms of a radioactive substance to decay, or the time it takes for half the initial quantity of a substance undergoing decay or reaction to be consumed or transformed.

Origin:

From the term "half-life period", first recorded in the mid-20th century, derived from the scientific study of radioactive decay.

Examples:

1. The half-life of carbon-14 is approximately 5,700 years.
2. In the nuclear industry, the half-life of certain isotopes is an important consideration in the safe storage and disposal of radioactive waste.
3. The half-life of a drug in the body determines how long it will remain effective and how quickly it will be eliminated.
4. By measuring the half-life of a substance, scientists can estimate the age of ancient artifacts and materials.
5. In pharmacology, the half-life of a drug determines the frequency at which it needs to be taken to maintain its therapeutic effect.