noun \ˈō-nəs\

Definition of onus

  1. 1 [Latin — more at onerous] a :  burdenb :  a disagreeable necessity :  obligationc :  blamed :  stigma

  2. 2 [New Latin onus (probandi), literally, burden of proving] :  burden of proof put forth a theory that left the onus squarely on him

onus was our Word of the Day on 02/20/2017. Hear the podcast!

Examples of onus in a sentence

  1. Consumers should be able to limit the use of information beyond what's essential to complete a transaction. There are two principal ways to do this: Web sites can permit them to “opt in,” or explicitly grant advance permission to share information. Or they can put the onus on consumers to “opt out” if they don't want information shared. —Consumer Reports, May 2000

  2. These laws got the regulatory ball rolling, but the onus was on the U.S. Food and Drug Administration (FDA) to ensure that additives were safe. —Amy Rosenbaum Clark, Vegetarian Times, March 1995

  3. It is not the scions of Yale and Harvard who apply to become FBI agents and construction workers and civil servants and cops who bear the onus of this reverse discrimination. —Thomas B. Edsall, Washington Post, 9-15 Mar. 1992

  4. hoping to avoid the onus of failure by lowering expectations ahead of time

  5. he perpetually tries to shift the onus for any mistakes onto other team members

Did You Know?

Understanding the etymology of onus is not at all burdensome; it's as simple as knowing that English borrowed the word - spelling, meaning, and all - from Latin in the 17th century. We can also add that it's a distant relative of the Sanskrit word for "cart" (a vehicle that carries a burden). English isn't exactly loaded with derivatives of Latin onus, but the root did give us "onerous" ("troublesome") and "exonerate" ("to clear from accusation or blame" - thus, "to unburden"). Additionally, our legal language has "onus probandi," which is often shortened to "onus." It means "burden of proof" - that is, the obligation of proving a disputed assertion in a court of law.

Circa 1640

First Known Use of onus

circa 1640

ONUS Defined for English Language Learners


noun \ˈō-nəs\

Definition of onus for English Language Learners

  • : the responsibility for something

Seen and Heard

What made you want to look up onus? Please tell us where you read or heard it (including the quote, if possible).


a rounded knoll or a ridge of ice

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