ADMENSURATIO

Definition

Admensuratio is a Latin term from old English law meaning admeasurement — the formal measurement or apportionment of something, typically land or a legal right, to determine each party's proper share. The term appears in early common law writs and proceedings concerned with correcting an excess or encroachment upon another's allotted portion. It is the Latinized procedural label for what English law called admeasurement, and the two terms are functionally interchangeable in historical legal sources.

Why It Matters in Research

This term belongs almost exclusively to the vocabulary of old English common law and will surface primarily in pre-modern writ registers, Year Books, and early treatise literature. Researchers should treat admensuratio as a gateway term: finding it in a source signals that the underlying substantive issue is one of admeasurement — most commonly admeasurement of dower or admeasurement of pasture — rather than a standalone doctrine in its own right. Two practical traps deserve attention. First, the term is rarely indexed in modern legal databases under this Latin form; searches should run in parallel under "admeasurement," "admensuration," and variant spellings including "admensuramento" and "admesuramentum," all of which appear in period sources. Second, the Registrum Omnium Brevium (Reg. Orig.), the writ register cited by both Black's editions, is the primary corpus source for this term in its procedural context. Researchers consulting that register will find admensuratio anchoring the formal writ language for admeasurement actions, particularly at folios 156–157. The term has no meaningful post-medieval survival as an operative legal concept. By the time of Blackstone and the systematic common law treatises, "admeasurement" had fully displaced the Latin form in practical usage, and the underlying writs themselves were largely obsolete before the Judicature Acts reorganized English procedure in the 1870s. For Law Mind corpus purposes, admensuratio is a diagnostic marker of pre-modern source material: its presence dates a document or confirms that a later source is drawing on archaic writ-register vocabulary.

Historical Dictionary Support

Both Black's first and second editions give identical, minimal treatment: admensuratio is defined simply as the Latin equivalent of "admeasurement" in old English law, with the sole citation being Reg. Orig. 156, 157. Neither edition elaborates on the substantive writs the term governed or the procedural contexts in which it arose. This minimalism is itself informative. The historical dictionaries treat admensuratio as a lookup bridge — a term a researcher might encounter in a Latin source who needs to be pointed toward the English-language doctrine — rather than as a concept requiring independent exposition. No divergence exists between the two Black's editions on this entry. The substance of admeasurement doctrine itself (the rules governing dower, pasture rights, and apportionment) must be pursued under the English-language headings in those same dictionaries and in the broader writ-register and treatise literature. One notable gap: neither Black's edition connects admensuratio to the parallel Scots law concept of a creditor's diligence for apportioning a debtor's estate (referenced in some editions under adjacent entries), nor to the insurance law usage of apportionment among underwriters. Those are separate lines of doctrine that share linguistic roots but not legal content.

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