1. the time required for a radioactive substance to decay to half its original mass or activity
Usage: physics, chemistry
2. the period during which something gradually loses strength, relevance, or effectiveness
Usage: figurative

Examples

• Carbon-14 has a half-life of about 5,730 years, making it useful for dating ancient artifacts.
• The half-life of uranium-235 is 704 million years.
• The medication's half-life in the body is approximately 6 hours.
• Once a celebrity scandal breaks, its half-life in the news cycle is usually just a few days.
• The half-life of a trending social media post is remarkably short.
• Scientists measured the half-life of the radioactive isotope in the laboratory.