Definition of onus probandi in US English:

onus probandi


  • The obligation to prove an assertion or allegation that one makes; the burden of proof.

    • ‘We must go with Huxley in his contention that these rights may sometimes be displaced; but the onus probandi lies heavily on the shoulder of him who disputes that claim to possession, not on the man who seeks to defend it.’
    • ‘[The first [is], that the onus probandi lies in every case upon the party propounding a Will; and he must satisfy the conscience of the Court that the instrument so propounded is the last Will of a free and capable Testator.’


Latin, ‘the burden of proving’.


onus probandi

/ˌōnəs prōˈbandē/