Definition
A Latin adjective meaning "common" or "shared," appearing in English legal sources primarily as a component of compound phrases rather than as a standalone term. In legal usage, *communis* qualifies a noun to indicate that a thing, right, error, or condition is held or recognized generally — by the public, by multiple parties, or by legal convention — as opposed to being particular, private, or individual. The term is encountered in Roman civil law materials and in the Latin-inflected legal vocabulary of early English common law and equity, where it persisted well into the nineteenth century in formal pleading and legal treatises.
Common Confusion
*Communis* is frequently encountered only in its compound forms, and researchers sometimes treat those compounds as unanalyzable technical terms without recognizing the structural role the adjective plays. Understanding that *communis* simply means "common" unlocks the meaning of a range of phrases: *communis error* (common error), *communis opinio* (common opinion), *communis stipes* (common stock, as in descent from a shared ancestor), and others. Treating these as opaque Latin labels rather than descriptive phrases can cause a researcher to miss closely related materials indexed under English equivalents.
Recognized Forms
/SUBTYPES
*Communis* appears in legal sources principally through its compound phrases. The most significant include:
**Communis error** — An error so widely shared and long-accepted that courts have treated it as law, or at least as a mitigating consideration. The maxim *communis error facit jus* ("common error makes law") expresses the idea that a mistake universally acted upon may harden into a legal rule. This phrase has a life of its own in equity and statutory interpretation discussions.
**Communis opinio** — The general or prevailing opinion among jurists or the legal community; used in civil law and early common law reasoning to indicate a consensus view carrying persuasive weight.
**Communis stipes** — The common ancestor or common stock from whom two or more persons descend; relevant in property law discussions of inheritance and in determining degrees of kinship.
**Communis dividundo** (or *actio communi dividundo*) — In Roman civil law, the action for partition of common property among co-owners.
Why It Matters in Research
Researchers working in the Law Mind corpus will encounter *communis* almost exclusively inside compound Latin phrases, not as a freestanding term. Three navigational points deserve attention.
First, indexing is inconsistent across historical dictionaries and digests. A phrase like *communis error* may be indexed under C (for *communis*), under E (for *error*), or under neither — absorbed instead into a discussion of maxims or equity principles. Cross-checking under each element of the compound phrase is essential.
Second, the phrase *communis error facit jus* has a contested interpretive history. Some authorities treat it as a serious rule of decision; others dismiss it as a dangerous maxim that allows entrenched mistake to masquerade as law. When this phrase appears in a historical source, the researcher should identify which camp the author belongs to before relying on the framing.
Third, *communis* compounds are translation-sensitive. Early English reporters and treatise writers sometimes rendered these phrases into English without signal — "common error," "common opinion," "common stock" — and sometimes left them in Latin. Corpus searches using only English equivalents will miss the Latin instances, and searches using only the Latin will miss the English renderings.
Historical Dictionary Support
The historical dictionaries reflect different editorial strategies for handling *communis*. Burrill's Law Dictionary takes the structurally honest approach, defining *communis* as simply "Common" and directing the reader forward to the compound phrases where the real content lives — a sensible choice for an adjective that carries no independent legal freight.
Anderson's Dictionary of Law does not define *communis* directly, instead cross-referencing to "ERROR, 1, Communis," which places the substantive content under the headword that matters most in practice. This approach reflects the reality that researchers reach *communis* through the phrase it qualifies, not on its own terms.
The Rapalje & Lawrence entry as captured in the source material appears to contain a transcription anomaly — the text pivots mid-entry into material concerning *charta* (charter, deed, written instrument) rather than developing *communis*. This cross-contamination of entries is a known hazard in digitized versions of multi-column historical dictionaries. Researchers should treat the Rapalje & Lawrence entry for *communis* as incomplete and consult the source volume directly.
None of the three dictionaries provides a comprehensive treatment of the full range of *communis* compounds. For *communis opinio* and the civil law uses, Bracton's *De Legibus* and the standard civil law glossaries (Calvinus's *Lexicon Juridicum*, for instance) are more productive than these English-language dictionaries.
Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Common Law Maxims; Error (Common Error); Partition (Common Property)