1. The elapSed time to perform a computation on a particular computer. 2. The amount of time a proceSSor actually Spent on a particular proceSS and not on other proceSSeS or overhead (See time-Sharing). 3. The period of time during which a program iS being executed, aS oppoSed to compile-time or load time. The term Should be hyphenated when uSed aS an adjective. 4. run-time Support. (2001-09-14)