noun
Computing term for running multiple tasks or processes concurrently.
このOSは多重タスク処理に優れている。
This OS excels at multitasking.
マルチタスク is a more common, casual loanword for multitasking in general, while 多重タスク処理 is a technical computing term.
Compound of 多重 (multiple) + タスク (task) + 処理 (processing).