Definition
A gallon. A Latin term used in old English legal texts to denote the unit of liquid measure equivalent to the gallon. The term appears in medieval Latin legal writing as a measurement unit, primarily in contexts regulating trade, weights, and measures.
Why It Matters in Research
Researchers encountering JALO in historical English legal manuscripts or plea rolls should recognize it immediately as a measurement term, not a proper name or substantive legal concept. The primary research trap is misreading the word in manuscript contexts where Latin abbreviations and archaic spellings are common — it may appear in close proximity to other archaic measure terms such as LAGENA (also meaning gallon) or units like the bushel or peck. Because English law historically regulated weights and measures through assizes — most notably the Assize of Bread and Ale — JALO will surface in documents touching on trade regulation, market offenses, and commercial disputes from the medieval period. Researchers should be aware that the gallon as a unit was itself subject to variation across commodities (wine gallon vs. ale gallon vs. corn gallon) and that a medieval document using JALO may not map cleanly onto any single modern gallon equivalent. Cross-reference against the specific commodity and century when precision matters.
Historical Dictionary Support
Burrill's Law Dictionary is the sole historical dictionary source for this term among standard legal lexicons. Burrill traces JALO to Fleta, the late thirteenth-century Latin legal treatise compiled during the reign of Edward I and modeled substantially on Bracton. The citation to Fleta, lib. 2, c. 11 locates the term in Fleta's discussion of weights and measures — a section dealing with standards of trade, the assize system, and the legal enforcement of uniform measures throughout England. Burrill offers no further elaboration, which is characteristic of his treatment of purely technical measurement terms. Black's Law Dictionary and Bouvier's Law Dictionary do not appear to carry this term, suggesting JALO remained confined to highly specialized historical usage and never entered the broader common law lexicon as a term of art. Researchers relying solely on Black's or Bouvier's for medieval Latin measure terms will find gaps; Burrill and direct consultation of Fleta itself remain the most reliable sources.
Jurisdictional Note
JALO is exclusively an old English legal term. It has no recognized counterpart or continued usage in American, Scottish, or other common law jurisdictions. Its relevance is limited to English legal history, primarily the medieval period.