Definition
A un is a Law French phrase meaning "at one" or "of one mind"; agreed; in accord. It expresses the state of being in agreement or consensus, particularly among parties to a legal proceeding or matter. The phrase appears in early English legal records, chiefly Year Book citations from the reign of Edward II, where it signals that parties have reached a common understanding on a point at issue — as in the illustrative phrase nous sumus à un de la tenaunce ("we are at one respecting the tenancy").
The term belongs to the vocabulary of pleading and practice in medieval English courts, where Law French served as the working language of procedure and record.
Common Language
Modern common usage (Wiktionary): "A un" has no established entry in modern English usage. The component words are recognizable — "a" as a French preposition meaning "at" or "to," and "un" as the French numeral or article meaning "one" — but the phrase as a unit carries no distinct legal or common meaning in contemporary English.
Historical common usage (Webster's 1913): Not entered. The phrase was already archaic by the nineteenth century and does not appear as a live term in general English dictionaries of that period.
The gap between common and legal meaning is largely a gap between existence and nonexistence. A modern reader encountering "à un" in a historical source would likely parse it as incidental French rather than recognize it as a term of art signaling party agreement on a contested matter.
Common Confusion
Burrill places a un in immediate proximity to the maxim A verbis legis non est recedendum ("from the words of the law there must be no departure"), an arrangement that can mislead a researcher scanning the page. The two entries are independent. A un concerns party agreement in pleading; the maxim concerns judicial fidelity to statutory text. They share no doctrinal connection beyond alphabetical adjacency.
Why It Matters in Research
A un is a term of narrow historical significance. Its practical value in the Law Mind corpus is twofold.
First, researchers working with Year Book materials from the reign of Edward I through Edward III will encounter Law French phrases of this type in pleading exchanges. Recognizing à un as a signal of party accord — rather than a proper name, a place, or an untranslated fragment — prevents misreading of the record.
Second, the phrase illustrates how medieval pleading procedure registered consensus. Courts and counsel needed a conventional vocabulary for noting that a contested issue had been resolved by agreement short of judicial determination. A un served that function in the oral and written culture of early common law pleading.
Researchers should note that the phrase does not appear in later English legal dictionaries with any operational significance. By the time systematic legal lexicography developed in the seventeenth and eighteenth centuries, Law French had been largely displaced, and terms like à un survived only as antiquarian citations. Modern research use is therefore confined to interpretive work on early Year Book sources and the history of pleading.
Historical Dictionary Support
Burrill's Law Dictionary is the sole source in the Law Mind corpus to enter this term, and its treatment is brief. Burrill gives the translation, the grammatical identification (Law French), a short illustrative phrase with translation, and two Year Book citations — Yearb. P. 1 Edw. II. 5 and T. 7 Edw. II. 240. No further elaboration is offered, and none appears to be warranted by the term's scope.
The adjacency to A verbis legis non est recedendum in Burrill's arrangement reflects nothing more than alphabetical sequencing; the two entries should not be read as connected principles.
No other major historical legal dictionary — not Bouvier, not Black's early editions, not Jacob's Law Dictionary — carries a un as a discrete entry, which confirms that the term was understood by the nineteenth century as a purely historical artifact rather than a working legal concept.
Jurisdictional Note
A un is a term of medieval English common law and has no recognized use in American, Scottish, or civilian legal traditions. It does not appear in any jurisdictional context outside the early English Year Books.
Encyclopedia Cross-Reference
Law Mind Encyclopedia: Statutory Interpretation (for the neighboring maxim A verbis legis non est recedendum and its doctrinal descendants); History of Pleading (for the Law French pleading context in which à un appears).