What is the definition of ratio decidendi in legal terms?

The definition of ratio decidendi refers specifically to the legal principle or rationale that is the foundation for a court's decision in a particular case. It encompasses the reasons given by the judge for reaching their conclusion, which serves as a guiding rule for future cases with similar facts or legal issues.

This concept is crucial in common law systems where precedents are highly valued; the ratio decidendi can be cited as authority in subsequent cases, ensuring consistency in the application of the law. While judges may express personal opinions or consider previous case law, it is the ratio decidendi that carries authoritative weight and is relied upon by lower courts in future rulings.