Definition
TIERCE carries two distinct meanings in legal sources, one from French law terminology and one from commercial and trade law.
1. (Law French) Third. Used in compound legal phrases, most notably tierce mein (also spelled tierce mein), meaning "third hand" — referring to a third party or intermediary holding property or acting in a transaction between two principal parties.
2. (Commercial/Trade Law) A unit of liquid measure equal to one-third of a pipe, or forty-two wine gallons. As a physical object, a tierce is a cask larger than a barrel but smaller than a hogshead or puncheon, used historically for shipping provisions such as salted meats, rice, and similar goods. Its legal significance arises in customs records, trade documents, excise regulations, and disputes over the measurement and taxation of liquid commodities.
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Common Language
Modern common usage (Wiktionary): A cask of a certain size, or the volume it contains used as a unit of liquid measure; larger than a barrel but smaller than a hogshead. Also: a third, a sequence of three playing cards of the same suit, the third canonical hour, a musical interval, or a fencing guard position.
Historical common usage (Webster's 1913): "A cask whose content is one third of a pipe; that is, forty-two wine gallons. A cask larger than a barrel and smaller than a hogshead or puncheon, in which salt provisions, rice, etc., are packed for shipment."
The common meaning is unusually close to one of the legal meanings here, because the commercial-measurement sense of tierce passed into law directly from trade practice. The divergence lies in the Law French usage: a reader encountering tierce in an older legal text outside of a commercial context should not assume it refers to a cask at all — it may simply mean "third," functioning as an adjective or prefix in a legal phrase that has nothing to do with liquid measure.
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Common Confusion
Tierce is easily confused with related archaic measures — particularly the pipe (84 gallons), the hogshead (63 gallons), and the barrel (31.5 gallons). Because historical statutes and trade documents used these terms inconsistently across commodities and jurisdictions, a tierce of wine, a tierce of provisions, and a tierce of oil did not always represent identical volumes in practice. Researchers should not assume a fixed modern equivalent without checking the specific commodity and period. The term is also visually and phonetically close to terce (the canonical hour), which appears in ecclesiastical and early common law records but carries no relationship to the liquid measure.
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Recognized Forms
/SUBTYPES
Tierce mein (also tierce mefn, tierce mein): The compound Law French phrase meaning "third hand," used in early English legal records to describe property passing through an intermediary or held by a third party. Appears in Britton (Britt. c. 120) and carried into early English legal dictionaries from that source.
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Why It Matters in Research
Researchers working in the Law Mind corpus will encounter tierce in two very different document types, and misreading which sense applies can send a research thread in the wrong direction.
In early common law and Norman-French influenced texts — particularly plea rolls, treatises like Britton, and land records — tierce functions as pure Law French for "third." The phrase tierce mein signals a property-law or procedural context involving a third party. A researcher unfamiliar with the French root may overlook this as an archaic cask reference when no commerce is at issue.
In customs records, excise legislation, admiralty cases, shipping documents, and colonial trade records, tierce is a unit of measure with real legal consequences for taxation, duties, and contract compliance. Here the precise volume matters, and the inconsistency of historical standards is a genuine trap: the wine tierce (42 wine gallons) differs from imperial measure equivalents, and statutory definitions varied by commodity. English and American customs statutes from the seventeenth through nineteenth centuries sometimes defined the tierce explicitly for particular goods; when they did not, disputes arose.
The Rapalje & Lawrence entry helpfully confirms the forty-two gallon standard but offers no further commercial context. Bouvier adds nothing substantive to the measure definition. Burrill captures both the Law French usage and the measure but keeps entries brief. None of the historical dictionaries address the inconsistency of the tierce across commodities — a gap researchers must fill from primary sources.
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Historical Dictionary Support
The historical dictionaries are in full agreement on the core definitions: tierce means "third" in Law French, and forty-two gallons as a liquid measure. All sources trace the Law French meaning to Britton, chapter 120, making that the authoritative early common law citation point. Burrill, the most etymologically precise of the shelf sources, correctly traces the word to the Latin tertius.
Where the historical record is thin: none of the dictionary entries address the use of tierce in shipping and customs disputes with any depth, nor do they flag the variability of the measure across time and commodity type. The Bouvier entry that appears in the source material is almost certainly misplaced in the corpus — its text concerns the Penal Servitude Act and convict licensing, which has no relationship to tierce. Researchers encountering that text under this headword in a Bouvier edition should treat it as a digitization or pagination error and consult a clean edition.
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Jurisdictional Note
The forty-two wine gallon standard for the tierce was recognized in both English and American commercial and customs practice, but imperial and wine gallon equivalents diverge (forty-two wine gallons equals approximately thirty-five imperial gallons). American customs and trade documents before and after the adoption of the U.S. customary system may use either standard. Researchers in colonial American records should verify which gallon measure applies.
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