noun
miscellaneous time; incidental time
Computing term for small, fragmented periods of time spent on non-primary tasks, such as context switching, interruptions, or minor overhead.
雑時間を減らすことで、開発の生産性が向上する。
Reducing miscellaneous time improves development productivity.
会議の合間の雑時間を有効活用したい。
I want to make effective use of the incidental time between meetings.
Compound of 雑 (ざつ, 'miscellaneous') and 時間 (じかん, 'time'). The exact origin is uncertain, but it likely arose in computing contexts to describe fragmented, non-productive time.