# onus

> English word · Noun · IPA /ˈəʊnəs/ · frequency rank #29,402

## Definitions
1. A legal obligation.
2. Burden of proof, onus probandi.
3. Stigma.
4. Blame.
5. Responsibility; burden.

## Etymology
Etymology tree
Proto-Indo-European *h₃enh₂-
Proto-Indo-European *-os
Proto-Indo-European *h₃énh₂os
Proto-Italic *onos
Latin onuslbor.
English onus
Learned borrowing from Latin onus (literally “burden”).

## Easily confused with
- **OS** (https://plainspell.com/en/vs/onus-vs-os)
- **ou** (https://plainspell.com/en/vs/onus-vs-ou)
- **out** (https://plainspell.com/en/vs/onus-vs-out)
- **our** (https://plainspell.com/en/vs/onus-vs-our)
- **ops** (https://plainspell.com/en/vs/onus-vs-ops)
- **oss** (https://plainspell.com/en/vs/onus-vs-oss)
- **oui** (https://plainspell.com/en/vs/onus-vs-oui)
- **OTS** (https://plainspell.com/en/vs/onus-vs-ots)
- **Ors** (https://plainspell.com/en/vs/onus-vs-ors)
- **OWS** (https://plainspell.com/en/vs/onus-vs-ows)
- **owns** (https://plainspell.com/en/vs/onus-vs-owns)
- **ours** (https://plainspell.com/en/vs/onus-vs-ours)
- **oops** (https://plainspell.com/en/vs/onus-vs-oops)
- **Otis** (https://plainspell.com/en/vs/onus-vs-otis)
- **owls** (https://plainspell.com/en/vs/onus-vs-owls)
- **opus** (https://plainspell.com/en/vs/onus-vs-opus)
- **onyx** (https://plainspell.com/en/vs/onus-vs-onyx)
- **ores** (https://plainspell.com/en/vs/onus-vs-ores)
- **oust** (https://plainspell.com/en/vs/onus-vs-oust)
- **on** (https://plainspell.com/en/vs/on-vs-onus)

## Common misspellings (4)
`onnus`, `onsu`, `onuss`, `ouns`

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/onus