on call

Idioms  

1. Available if summoned, as in Medical residents are required to be on call at least three nights a week. This expression originated as at call in the late 1500s. Also see at someone's beck and call.

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Example Sentences

But if I find a great deal, and it’s on call number seven, I’m going to call you up and say, “Hey, I think this is an amazing deal. You should take it, and I’m going to give you all the evidence why.”

From The Wall Street Journal

Lawyers say the trade court keeps a judge on call to act quickly when parties come to court seeking an emergency intervention and that was likely how the refund issue ended up in Eaton’s lap.

From The Wall Street Journal

While he worked with Rojas, Battle’s complaint alleges, she required him “to be on call 24/7” and do her personal errands.

From Los Angeles Times

"Each time we have reached out to the public, we've been provided with some lines of inquiry to follow up on, but unfortunately none have proven to be the key to finding out who this person is," said Ponting, who was on call the day the man's body was found and has led the case ever since.

From BBC

The team of specialists is on call 24 hours a day to collect the most poorly children and babies and take them to intensive care, supporting 27 hospitals across the south of England.

From BBC