Onus

Onus denotes a burden of responsibility or obligation that rests on an individual or organization. It can be moral, ethical, social, or legal in nature. In everyday use, phrases such as 'the onus is on you to decide' highlight the duty to take action or justify a position. The term often signals accountability rather than simply a duty and is common in formal or analytical writing.

In legal contexts, the onus of proof refers to who must establish a claim or defense. In criminal cases the prosecution bears the onus to prove guilt beyond a reasonable doubt; in civil cases the plaintiff typically has the onus to prove the claimed facts and damages. The phrase can also appear as 'to shift the onus' or 'to bear the onus,' emphasizing responsibility transfer.

Etymology and nuance: Onus comes from Latin onus meaning burden, load. The English usage dates from the 15th century and has retained a formal register. Related terms include burden, obligation, and responsibility; 'onus' is often used in policy, legal analysis, or professional discourse to stress duty rather than just inconvenience. See also burden of proof.