ONUS

Latin: the burden. It is usually used in the context of evidence. The onus of proof in criminal cases lies with the state. It is the state that has the burden of proving beyond reasonable doubt. In civil cases, the onus of proof lies with the plaintiff who must prove his case by balance of probabilities. So "onus" refers both to the party with the burden, and to the scope of that burden, the latter depending whether the context is criminal or civil.