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

Having a good contractor on call is now a must-have for companies building power plants, and they are willing to pay up for them.

From Barron's • May 4, 2026

After his mother died — a loss reflected in his fiction — he moved in with his now-wife and was on call to help with her funeral home.

From Los Angeles Times • Apr. 16, 2026

U.S. companies spent an estimated $23.5 billion on call and contact center outsourcing in 2025, according to market research firm Precedence Research.

From The Wall Street Journal • Mar. 26, 2026

I thought it was an injury from Pilates, but, after a couple of weeks of the pain, I went to see the nurse practitioner on call at my doctor’s office.

From The Wall Street Journal • Feb. 13, 2026

“Tim and I are doing well. He sends his love. He really wanted to be here, but he’s on call tonight and had to go in.”

From "Piecing Me Together" by Renée Watson