1 : the time required for half of something to undergo a process: as a : the time required for half of the atoms of a radioactive substance to become disintegrated b : the time required for half the amount of a substance (as a drug or radioactive tracer) in or introduced into a living system or ecosystem to be eliminated or disintegrated by natural processes
2 : a period of usefulness or popularity preceding decline or obsolescence <slang usually has a short half-life>
2 : a period of usefulness or popularity preceding decline or obsolescence <slang usually has a short half-life>
For americium-241, it is known that half of the atoms decay in 458 years. Therefore, 458 years is the half-life of americium-241. Every radioactive element has a different half-life, ranging from fractions of a second to millions of years, depending on the specific isotope. For example, americium-243 has a half-life of 7,370 years.
by Mark January 06, 2004

by Mark March 08, 2005

by Mark May 13, 2005

another word for the anus; not to be confused with the nether eye (a word used by chaucer in the canterbury tales), which refers to a woman's genitalia (read: vagina).
by mark February 02, 2004

by Mark January 04, 2005

Homer points to a map of the world, pointing to Uruguay he says:hhehehehe look at the name of this country! U R Gay!
by mark December 08, 2003

by Mark December 21, 2004
