Definition
"Magna" as a standalone legal term appears in two distinct historical English law contexts:
1. (Customs and Trade Law) The old export duties levied on wool, sheepskins or woolfels, and leather. Also called the "great custom," magna custuma referred to the principal ancient customs assessed on these commodities at English ports, as distinct from the parva custuma (petty custom) applied to other goods and to alien merchants.
2. (Historical Geography / Roman Toponymy) A Latin place-name element meaning "great" or "large," used in the identification of Roman-era settlements in Britain. Burrill records "Magna" as the Roman name for Chester in the Wall (near Haltwhistle in Northumberland), distinguishing it from similarly named sites. It appears in variant forms—Magnitum, Magionimum, Magovinium, Magiovintum—applied to Dunstable in Bedfordshire.
Neither usage reflects a general legal doctrine. Both are specialized historical references most likely to appear in antiquarian legal writing, land records, or customs documentation from the medieval and early modern English periods.
Common Language
Modern common usage (Wiktionary): "Magna" as a standalone English word is the plural of "magnum" (as in a large-format bottle or firearm cartridge).
Historical common usage: In Latin, "magna" is the feminine singular (or neuter plural) form of "magnus," meaning great, large, or important. Familiar to most readers today through "Magna Carta" — the Great Charter.
The gap matters for researchers: encountering "magna" alone in a historical legal source does not mean a reference to Magna Carta, nor does it carry the constitutional weight of that document's name. In customs records, it signals a specific fiscal category; in geographic or antiquarian legal texts, it identifies a Roman site. Neither usage generalizes.
Common Confusion
"Magna" standing alone is frequently assumed to be a shorthand for Magna Carta. In legal research, this assumption is almost always wrong. Magna Carta is a distinct document with its own substantial doctrinal history; "magna" as used in the customs law context (magna custuma) and in the toponymic context recorded by Burrill has no connection to that document. Researchers should also not conflate magna custuma with tunnage and poundage or other later English customs regimes, which operated under different statutory authority.
Why It Matters in Research
Researchers are most likely to encounter "magna" as a standalone term in one of three situations: (1) medieval customs records and treatises on English trade law, where magna custuma denotes the principal wool and leather export duties; (2) antiquarian legal and historical geography texts, where it identifies Roman settlements relevant to title chains, boundary disputes, or ecclesiastical records tied to specific places; or (3) as a prefix in compound terms (magna custuma, Magna Carta, magna assisa) where the meaning derives from context.
The customs law usage is the more practically significant for legal research. The magna custuma was established in the reign of Edward I and governed English wool exports during a period when wool was England's primary export commodity. Documents from this period—port books, customs accounts, writs of estreat—may use "magna" as shorthand for the great custom without further elaboration, assuming the reader's familiarity. Modern researchers approaching these records without that background risk misreading or overlooking the fiscal significance of the term.
The toponymic entries in Burrill are a reminder that early English legal dictionaries served double duty as antiquarian reference works. Place identification mattered for establishing jurisdiction, reading ancient grants, and interpreting boundary descriptions in deeds and charters. A legal instrument referencing "Magna" as a place needed to be keyed to a specific location, and Burrill's entries provide that key for two sites.
Historical Dictionary Support
Rapalje & Lawrence define magna narrowly and correctly as the old export duties on wool, sheepskins or woolfels, and leather — the magna custuma of English customs law. The entry is terse but accurate.
Burrill takes a different approach entirely, using "Magna" as a geographic headword to identify Roman-era British settlements. His entries reflect the antiquarian tradition of English legal lexicography, in which dictionaries were expected to assist with the identification of places named in ancient records. The two dictionaries do not conflict; they address entirely separate usages of the same Latin word.
Neither dictionary addresses Magna Carta under this headword, correctly treating that document as a separate entry. Neither dictionary provides doctrinal analysis, which is appropriate given that "magna" alone carries no independent legal doctrine.
What the historical dictionaries miss: no discussion of the fiscal mechanics of the magna custuma, its relationship to the parva custuma, or the statutory framework governing wool exports. Researchers needing that depth should consult specialized histories of English customs law rather than general legal dictionaries.