無常 anitya. Impermanent; the first of the 三明 trividyā; that all things are impermanent, their birth, existence, change, and death never resting for a moment.
http://www.acmuller.net/soothill/soothill-hodous.html#body.1_div.1
2009-08-17 10:49:05 補充:
some other useful tools for buddhism tranlation :
http://ccbs.ntu.edu.tw/new/tools/tools.htm
enjoy!