1
[Latin — more at onerous]
b
: a disagreeable necessity : obligation
c
: blame
d
: stigma
2
[New Latin onus (probandi), literally, burden of proving] : burden of proof
put forth a theory that left the onus squarely on him

Did you know?

Understanding the etymology of onus shouldn’t be a burden; it’s as simple as knowing that English borrowed the word—spelling, meaning, and all—from Latin in the 17th century. Onus is also a distant relative of the Sanskrit word anas, meaning cart (as in, a wheeled wagon or vehicle that carries a burden). English isn’t exactly loaded with words that come from Latin onus, but onerous (“difficult and unpleasant to do or deal with”) is one, which is fitting since in addition to being synonymous with “burden,” onus has also long been used to refer to obligations and responsibilities that one may find annoying, taxing, disagreeable, or distasteful.

Examples of onus in a Sentence

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
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
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
hoping to avoid the onus of failure by lowering expectations ahead of time he perpetually tries to shift the onus for any mistakes onto other team members
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Entering the final year of his contract, the onus is on Hoyer to win now. Paul Sullivan, Chicago Tribune, 9 Mar. 2025 House Democrats from across the party's ideological spectrum have argued the onus of averting a government shutdown falls squarely on Republicans, who control Congress and the White House. Andrew Solender, Axios, 7 Mar. 2025 Meta, the parent company of Facebook and Instagram, and social media apps X and Snap believe the onus to verify kids’ ages is on the app stores following criticism that technology devices and social media networks are causing harm to minors. Miranda Nazzaro, The Hill, 6 Mar. 2025 Since the law puts the onus of verifying users' age on app store operators such as Google and Apple, social media platforms, which have long been blamed for not doing enough to protect kids online, welcome the bill. Jibin Joseph, PCMAG, 6 Mar. 2025 See All Example Sentences for onus

Word History

First Known Use

1626, in the meaning defined at sense 1a

Time Traveler
The first known use of onus was in 1626

Podcast

Cite this Entry

“Onus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/onus. Accessed 15 Mar. 2025.

More from Merriam-Webster on onus

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!