The period when a program is running/being executed/doing some hopefully useful work, as distinct from compile-time when the program is being translated.[ edit] S to Z

actual time during which the program is executing. Some errors can only be caught at run-time.

Run-time, in contrast to design-time, means that courseware is seen from the learner's point of view, i.e. when the course is running (played back) on the client machine.