be on
Idioms-
Be taking medication or an illegal drug, as in Are you on some antibiotic? or He was definitely on narcotics when it happened . [1930s]
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Be in favor of something or willing to participate, as in We're going dancing after the play—are you on? [ Colloquial ; late 1800s]
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Be engaged in some action, especially on the stage, as in Hurry up, you're on in five minutes . [Late 1700s]
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Perform extremely well, as in I can't return Dan's serve—he's really on today . [ Slang ; second half of 1900s]
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Be scheduled, as in Is tonight's rally still on? [ Colloquial ; second half of 1990s]
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be on one . Be at one's expense, either as a treat or the butt of a joke. For example, This round of drinks is on me , or He enjoys a good laugh, even when the joke's on him . [ Colloquial ; second half of 1800s]
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not be on . Be unacceptable, not allowable, as in I can't believe you'd cancel; that's just not on . This usage is more common in Britain than America. [ Colloquial ; 1930s] For a synonym, see not done . Also see be on to .
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see be on.
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.
Even if policymakers do hold rates steady, all eyes will be on whether any voting members of the 12-member committee dissent.
From Barron's ● Jul. 28, 2026
They reminded him that he’s expected to be on the Hall’s Era Committee ballot in December.
From Los Angeles Times ● Jul. 28, 2026
The iPhone and Apple Watch will be offered on 12- and 24-month terms while iPad and Mac will be on 24- and 36-month terms.
From MarketWatch ● Jul. 28, 2026
Bryans said in the 1990s a lot of people "were reluctant to come to Northern Ireland, but when they heard Gerry Kelly" they all wanted to be on the show.
From BBC ● Jul. 27, 2026
Please, please be on the lookout for us.
From "Across So Many Seas" by Ruth Behar
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
