Synonyms

on call

Idioms

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.

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

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

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

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 • Mar. 8, 2026

New rules will mean reservists remain on call for an extra decade, and lower the threshold for them being called into service.

From BBC • Jan. 15, 2026

He was on call to take care of the monkeys if they became sick or needed medical attention.

From "The Hot Zone" by Richard Preston

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023