Definition
Major annus (Latin: "the greater year") is the historical legal term for a leap year — a calendar year of 366 days, produced by the addition of an intercalary day to February. The term appears in medieval common law texts and was relevant to the precise computation of time periods in legal instruments, writs, and property transactions where exact day-counts mattered.
The counterpart term is annus (or annus communis), the ordinary year of 365 days.
Why It Matters in Research
This term will surface almost exclusively in pre-modern common law sources and Latin legal texts. A researcher encountering major annus in a medieval writ, conveyance, or treatise reference should understand it as a technical calendar term, not a substantive legal concept with doctrine attached to it. Its appearance typically signals that the surrounding passage is computing a limitations period, term of years, or other time-measured obligation with calendrical precision.
The single consistent authority cited across all dictionary sources is Bracton (Bracton, De Legibus et Consuetudinibus Angliae, fol. 359b), the thirteenth-century treatise that is a foundational source for much of the Law Mind corpus's coverage of early English common law. Researchers working in that stratum of the corpus should note that Bracton's treatment of time computation — including the distinction between the common year and the leap year — reflects Roman-derived learning adapted to English practice.
For modern research, the term has no operative legal significance. Contemporary statutes and rules governing time computation address leap years either expressly or by absorbing them into standard day-count methods (for example, the common rule that a period stated in years runs to the same date in the target year regardless of intervening leap days). No modern legal test or doctrine turns on the major annus/annus communis distinction.
Historical Dictionary Support
Black's Law Dictionary (both the first and second editions) and Burrill's Law Dictionary are in complete agreement on this term: all three define it as "the greater year; the bissextile year, consisting of 366 days" and all three cite Bracton fol. 359b as the authority. The uniformity is unsurprising — this is a Latin calendar term with a fixed referent, leaving no room for doctrinal divergence.
The spelling varies slightly across editions (Black's 2nd ed. renders it "bisaextile," likely a typographical variant of "bissextile"), but the meaning is consistent.
What the historical dictionaries do not address is any substantive legal consequence of a year being major annus versus ordinary. The entries function as glosses — translations of a Latin term encountered in older sources — rather than as explanations of a legal rule. Researchers should not infer from their presence in these dictionaries that the leap year distinction generated significant litigation or doctrinal development in English or American law.
Jurisdictional Note
The term belongs to the Latin lexicon of medieval English common law and has no distinct American doctrinal history. It does not appear in American statutory law. Jurisdictional variation is not a meaningful research consideration for this term.
Encyclopedia Cross-Reference
No Law Mind Encyclopedia entry addresses the computation of calendar years in historical common law sources. The matching entries returned (family_96, ip_3, environmental_48) are not relevant to this term.