Definition
Non usus (Latin/Law Latin: "non-use") is a term from old English law referring to the failure to exercise or make use of a right, franchise, office, or privilege. Non-user — the anglicized form — describes a neglect or omission to exercise a granted right over time, which could in certain contexts result in forfeiture or extinction of that right.
The concept operates on the principle that rights, particularly those granted by the crown or arising from franchise, could be lost through prolonged non-exercise. It stands as the passive counterpart to misuser (abuse of a right): where misuser involved wrongful exercise of a franchise or office, non usus involved simply failing to exercise it at all.
Common Confusion
Non usus and misuser are frequently treated as a matched pair in old English law but are not interchangeable. Misuser refers to the improper or wrongful use of a franchise or right — the holder exercises the right but does so abusively. Non usus refers to the complete failure to use the right at all. Courts and commentators treated these as distinct grounds for forfeiture proceedings, and historical sources address them separately. A researcher encountering one should not assume the other applies.
Non usus should also be distinguished from abandonment in modern property law. Abandonment requires a showing of intent to relinquish a right. Non usus in the old English framework was more objective: prolonged non-exercise could itself supply grounds for forfeiture without necessarily proving subjective intent to abandon.
Why It Matters in Research
This is primarily a term of historical and archival significance. Researchers encountering non usus in older English legal materials — particularly in records touching on franchises, charters, corporate grants, or crown-granted offices — should recognize it as a procedural ground for quo warranto proceedings or other forfeiture actions. It will not typically surface in modern American case law as a live doctrine.
The key navigational point: non usus appears most often in the context of franchise law, where the crown could reclaim a granted privilege upon a showing that the grantee had let it lapse. Fleta (the late 13th-century English legal treatise cited by Burrill) addresses this in the context of legal offices and franchised rights. Researchers working with Bracton, Fleta, or early Yearbook materials on franchise forfeiture will encounter this term in that doctrinal neighborhood.
For American legal history researchers, the concept has some relevance to early corporate charter law and the forfeiture of corporate franchises by state legislatures or courts, though American sources more commonly use "non-user" or address the concept through quo warranto doctrine rather than by invoking the Latin phrase directly.
Trap for historical researchers: the term's rarity in American sources can lead to under-recognition. When reading early American treatises on corporations or municipal franchises — Story, Kent, Angell & Ames on corporations — the underlying concept of non-user as a basis for forfeiture is present even when the Latin phrase is absent.
Historical Dictionary Support
Burrill's Law Dictionary provides the entry in full economy: "Non-user. Fleta, lib. 4, c. 18, § 2." This single-line entry reflects how the historical dictionaries treat non usus — as a term whose meaning was considered self-evident to readers trained in Latin and familiar with the old English franchise system. The entry's brevity is itself informative: it was not a contested or multi-layered concept, but a straightforward descriptive label for a recognized legal condition.
No other shelf sources in the current corpus provide extended treatment of non usus. The absence of elaboration in the historical dictionaries suggests the term functioned more as a technical label in pleading and treatise writing than as a term requiring interpretive definition. Its meaning was carried primarily by context — franchise law, quo warranto, and the law of offices.
Fleta itself (the source cited by Burrill) is a late 13th-century treatise compiled by an unknown author, possibly while imprisoned in Fleet prison — hence the title. It draws heavily on Bracton and represents the doctrinal framework of Edwardian English law. Researchers working with Fleta should treat it as reflecting pre-statutory, customary English franchise doctrine.
Jurisdictional Note
Non usus as a Latin term is effectively confined to English legal history and early common law materials. American jurisdictions absorbed the underlying concept through quo warranto doctrine and corporate forfeiture law but generally expressed it in English as "non-user." Civil law jurisdictions have analogous but doctrinally distinct concepts (prescription of rights through non-exercise) that should not be conflated with the common law framework.