From Longman Dictionary of Contemporary Englishhalf-lifeˈhalf-life noun [countable] HPthe length of time it takes a radioactive substance to lose half of its radioactivity
Examples from the Corpus
half-life• The time it takes for a dose of a drug to wear off is measured by a value called a half-life.• But it has a half-life of just 140 days so there can be little delay manufacture and its incorporation into a bomb.• With a half-life of 12 years, tritium could build up in the Tamar estuary and eventually enter the human food chain.• The more complete descriptive term is drug elimination half-life.• The time taken for half of the atoms of a radioactive isotope to decay is called its half-life.• No one has a long half-life as the star of the program.• These effects are less marked with fentanyl because of its shorter serum half-life.• The daily intake should be divided into at least three doses because of the short half-life. 