Definition
An obsolete abbreviation and term appearing in Latin legal maxims and medieval English law texts. "Mun" in legal usage is best understood as a fragment of Latin terminology rather than a freestanding legal concept. It appears principally as a contracted or truncated form drawn from the Latin root *munus* (plural: *munera*), meaning a duty, gift, office, or public burden. In old English legal writing, the term surfaces in the context of municipal or civic participation — specifically in the principle that *municipes* are those who share in public offices and duties (*muneris participes*), having been received into the civic body so that they share public burdens (*munera*) in common.
The fuller legal context, as preserved in Burrill's citation to Coke's *Institutes* (2 Inst. 219), concerns the definition of municipal persons — those who hold or are eligible to hold civic office — and the obligations attached to civic membership. The Latin formulation (*Proprie municipes appellantur muneris participes, recepti in civitatem, ut munera nobiscum fungamtur*) translates roughly as: "Properly, those are called municipes who share in office, received into the city so that they may perform public duties with us." The word "mun" appearing in Burrill reflects either abbreviation of *municipes* or a corruption in transcription common to early printed law dictionaries.
Common Language
Modern common usage (Wiktionary): "Must" — an archaic or dialectal auxiliary verb.
Historical common usage (Webster's 1913): The mouth — an obsolete slang term, illustrated by a nursery rhyme.
Neither the archaic auxiliary nor the slang anatomical term has any connection to the legal usage. The legal appearance of "mun" derives entirely from Latin, not from English vernacular. A researcher encountering "mun" in a historical English legal text should not assume any relationship to these common-language meanings.
Why It Matters in Research
Researchers encountering "mun" in historical legal sources should treat it as a contextual fragment, not a defined standalone term. Its significance lies almost entirely in what it abbreviates or precedes. Two research traps are worth flagging:
First, Burrill's entry is fragmentary — the surviving text is clearly a partial transcription, cutting off mid-passage. Researchers relying solely on Burrill for this term will find the entry inconclusive and should trace the underlying Latin directly to Coke's *Institutes*, Book II, at page 219, which discusses the nature of municipal corporation membership and the obligations of civic office.
Second, do not conflate this Latin-root usage with the modern colloquial abbreviation "mun" (short for *municipality* or *municipal*), which appears frequently in modern administrative law, local government statutes, and planning documents. The historical legal usage is etymologically connected but conceptually narrower — it concerns the Roman and medieval concept of civic duty and office-holding, not the modern administrative entity.
For corpus researchers: this term is most likely to appear in early English legal treatises citing Roman civil law sources, in Coke-era materials discussing municipal corporations, and in any Law Mind sources touching on the nature and obligations of civic office. Cross-reference with entries on *municipal corporations*, *office*, and *munus* where available.
Historical Dictionary Support
Burrill's Law Dictionary is the only shelf source providing a legal definition, and the entry is notably damaged — the text breaks off mid-Latin quotation, leaving the reader with a partial gloss on *municipes* and an incomplete citation thread. Burrill correctly links the term to the concept of office-sharing and civic duty, and his citation to 2 Inst. 219 is sound and traceable.
What Burrill's entry misses, likely due to truncation: the full classical formulation distinguishing *municipes* (those with civic obligations) from mere *incolae* (residents without full civic standing) — a distinction that had real legal consequence in determining eligibility for office, tax obligations, and civic privileges in both Roman law and its English common law reception.
No other historical dictionaries in the current Law Mind shelf (Bouvier, Black's, Jacob's) carry a dedicated "mun" entry, reflecting that this is properly a fragment of Latin legal vocabulary rather than an English common law term of art.