half-life

Definitions

General Science

• noun the time required for an organism to eliminate naturally half the amount of a substance that has entered its body

Astronomy

• The time taken for half of the atoms of an unstable isotope to decay. Half-lives can be under a second (0.3 seconds for Sodium 20) or millions of years (about 4.5 billion years for Uranium 238).

Banking

• noun the number of years needed to repay half the capital borrowed on mortgage

Construction

• The period of time that the level of radioactivity for a substance decays by 50%.

Electronics

• The time interval that elapses for a given radioactive substance to lose half of its radioactive intensity. That is, it is the time required for half the atoms of a given sample of identical nuclides to undergo decay. The half-life of ⁵⁰V (an isotope of vanadium), for instance, is approximately 1.4 × 10¹⁷ years, while that for ⁶Be (an isotope of beryllium) is approximately 5.9 × 10^-21 seconds. Also called radioactive half-life.

Food

• noun the time taken for half the cells in a tissue sample to die and be replaced

Medical

• noun a measurement of the period of time taken before the concentration of a drug has reached half of what it was when it was administered
• noun the time taken for half the atoms in a radioactive isotope to decay

Nearby Definitions of “half-life”

• habit
• hack
• hacker
• haggis
• hair
• half-life
• Hallam family
• halo-
• ham
• hamburger
• Hamlet, Prince of Denmark

Contexts for “half-life”

8 definitions in context
• General Science
• Astronomy
• Banking
• Construction
• Electronics
• Food
• Medical