The onus is the duty or blame that rests on somebody. The onus is on you, shift the onus, the onus of proof.
It appears almost only in the onus is on, and the onus of proof is who has to prove a case, which decides most of them. The Latin means a burden, and onerous comes from the same word.
1nounonusThe duty or blame that rests on somebody.
“The onus is on the landlord to repair the heating, not the tenant.”
onus is a duty.
Latin onus means a burden; onerous is built on the same word.
Latin
onus
English, today
onus
Learned borrowing from Latin onus. Latin onus literally “burden”.
Etymology from Wiktionary, CC BY-SA