On call means available to be summoned at any hour. Not at work, and not free either.
It is a formal arrangement in medicine, plumbing, IT and the emergency services, and being on call usually carries an allowance because it restricts your whole evening. Doctors on call sleep in their clothes. The phrase is written as two words. On duty is different, since that means actually working, and on standby is closer, meaning ready and waiting but usually already at the place.
1phraseon callAvailable to be called on for work at any time.
“He is on call every third weekend.”
Practised in A Man Called Ove, Emergency & Rescue
First appears in chapter 4 of A Man Called Ove.
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