Plain-English explanations of the Latin terms, doctrines, and procedural shorthand you’ll meet in your first year of law and beyond.
Latin: 'the reason for deciding'. The legal principle that determines the outcome of a case. The ratio binds future courts under the doctrine of precedent. Distinguish from obiter dicta — comments not strictly necessary to the decision.
Related: Obiter dicta · Stare decisis · Precedent
Latin: 'things said by the way'. Judicial observations not essential to the decision. Persuasive but not binding. Often becomes ratio in later cases.
Related: Ratio decidendi
Latin: 'to stand by things decided'. The doctrine of binding precedent: courts must follow earlier decisions of higher courts on the same legal point.
Related: Ratio decidendi · Precedent · Per incuriam
Latin: 'through lack of care'. A decision reached in ignorance of a binding statute or precedent. Such decisions may be set aside by a court that would otherwise be bound to follow them.
Related: Stare decisis
Latin: 'guilty mind'. The mental element of a criminal offence — the state of mind the prosecution must prove to secure conviction (intention, recklessness, knowledge, or negligence depending on the offence).
Related: Actus reus · Strict liability
Latin: 'guilty act'. The physical conduct element of a criminal offence — the act, omission, or state of affairs that the defendant must be shown to have caused.
Related: Mens rea · Causation
Liability without proof of mens rea. The prosecution need only prove the actus reus. Common in regulatory offences (e.g. food safety) where Parliament expressly or impliedly excludes the mental element.
Related: Mens rea
A person who commits a tort. Joint tortfeasors are jointly and severally liable for the same loss.
Liability of one party (typically an employer) for the tortious acts of another (typically an employee) committed in the course of employment. Test of 'close connection' between act and employment context — see Lister v Hesley Hall, Mohamud v Morrison.
Related: Tortfeasor · Course of employment
Something of value given by each party to a contract. Must be sufficient (recognised by law) but need not be adequate (proportionate). Past consideration is not good consideration.
Related: Promissory estoppel · Privity
An equitable doctrine preventing a party from going back on a promise where the promisee has acted in reliance on it. A shield, not a sword — generally cannot be used to found a cause of action. See Central London Property Trust v High Trees House.
Related: Consideration · Equity
The principle that only parties to a contract can sue or be sued on it. Modified by the Contracts (Rights of Third Parties) Act 1999 in England and Wales.
Related: Consideration
A bar preventing a party from asserting something inconsistent with a previous position they've taken, where the other party has relied on that position.
Related: Promissory estoppel
A body of law historically administered by the Court of Chancery, focused on fairness and discretion. Now fused administratively with the common law but doctrinally distinct. Source of trusts, injunctions, specific performance, estoppel.
Related: Trust · Injunction
An equitable arrangement under which property is held by a trustee for the benefit of a beneficiary. Three certainties required: intention, subject matter, objects (Knight v Knight).
Related: Equity · Beneficiary
A person for whose benefit property is held under a trust. Distinct legal and equitable interests.
Related: Trust
Latin: 'you shall have the body'. A writ requiring the physical production of a detained person before a court, to challenge the lawfulness of their detention. A core constitutional safeguard.
Latin: 'beyond the powers'. A doctrine in administrative law: a public body cannot lawfully act outside the powers granted to it by statute. Decisions taken ultra vires can be quashed on judicial review.
Related: Judicial review
The High Court's supervisory jurisdiction over public bodies. Grounds: illegality, irrationality, procedural impropriety, proportionality (in human-rights and EU-law-adjacent cases).
Related: Ultra vires · Wednesbury
The standard of irrationality in judicial review, from Associated Provincial Picture Houses v Wednesbury Corporation [1948]. A decision is Wednesbury unreasonable if it is 'so unreasonable that no reasonable authority could ever have come to it'.
Related: Judicial review
The link between conduct and harm. In criminal law and tort: factual causation ('but for' test) and legal causation (no novus actus interveniens). See R v Smith, Wagon Mound (No 1).
Related: Actus reus
Latin: 'a new intervening act'. An event breaking the chain of causation between the defendant's act and the claimant's harm.
Related: Causation
Latin: 'no one gives what they do not have'. A seller cannot transfer better title to goods than they possess. Subject to statutory and common-law exceptions.
Latin: 'let the buyer beware'. The historical rule that buyers bear the risk of undisclosed defects. Substantially modified by the Consumer Rights Act 2015 and Sale of Goods Act 1979.
Latin: 'place to stand'. The right of a party to bring an action — i.e. that they have sufficient interest in the matter. Especially relevant in judicial review.
Related: Judicial review
Latin: 'no injury is done to one who consents'. A defence in tort: a claimant who voluntarily assumes a known risk cannot sue for resulting harm.
French: 'superior force'. A contractual clause excusing performance where extraordinary, unforeseen events make performance impossible. Distinct from frustration at common law.
Related: Frustration
Common-law doctrine discharging a contract where, without fault, performance becomes impossible, illegal, or radically different. See Davis Contractors v Fareham UDC.
Related: Force majeure
An equitable remedy compelling a party to perform their contractual obligations. Discretionary; usually only granted where damages are inadequate (e.g. unique goods, land).
Related: Equity
An equitable remedy ordering a party to do (mandatory) or refrain from doing (prohibitory) something. May be interim or final.
Related: Equity
The Oxford University Standard for Citation of Legal Authorities. The dominant UK legal citation format. Footnote-driven; sparse punctuation. Try our free generator at /tools/oscola.
Every term here links to the cases that define it in our case library. Search by term or browse by topic.