runtimePronunciation: /ˈrʌntaɪm/Definition of runtime noun 1the time that a film or DVD lasts:a thriller that is so well paced it seems a lot shorter than its three-hour runtime 2 Computing the length of time a program takes to run: the device uses undisclosed proprietary technology to reduce report run-times the time at or during which a program is run: files whose names are only known at run-time a cut-down version of a program that can be run but not changed: you can distribute the runtime to your colleagues adjective (of software) in a reduced version that can be run but not changed. runtime in other Oxford dictionaries Definition of runtime in the US English dictionary