IPA: /ˈwɜːrkaʊt/
KK: /ˈwɜrkˌaʊt/
A period of physical exercise or training to improve fitness or performance.
I go to the gym for a workout every morning.
Workout → It is formed from "work" (from Old English *weorc*, meaning physical or mental effort) and "out" (meaning outside or away). The word "workout" refers to a session of physical exercise or effort, typically done outside of regular work activities.
Think of putting in physical 'effort' ('work') and doing it 'outside' of your usual routine ('out') — that's what a workout means.
No commonly confused words.