Meaning of ratio decidendi in English:

ratio decidendi

Pronunciation /ˌdɛsɪˈdɛndiː/

nounplural noun rationes decidendi/ˌratɪˈəʊniːz/

  • The rule of law on which a judicial decision is based.

    ‘Courts are bound by principles of law, the ratio decidendi of cases.’
    • ‘The former are described as being the ratio decidendi (reasons for the decision).’
    • ‘If property suddenly became available all over the country many of the rationes decidendi of the past would be quite inappropriate.’
    • ‘You must then deal fully with the ratio decidendi of the case, with a detailed analysis of Lord Templeman's judgment on behalf of the majority.’
    • ‘I do not find it easy to discover the ratio decidendi of Pook's case.’
    • ‘If the Court refuses that, there are some interesting arguments about how one determines ratio decidendi.’


Latin, literally ‘reason for deciding’.