Definition
A Latin legal term meaning "to be unknown" or "not to know." In classical legal usage, ignorari functions as the passive infinitive of the verb ignorare — to be ignorant of, to have no knowledge of a thing. It appears principally in Latin maxims and formulaic expressions carried forward from English common law into early American legal writing and pleading.
The term is closely related to, and frequently encountered alongside, the grand jury formula ignoramus ("we do not know it" or "we ignore it"), which shares the same root. Ignorari itself, however, is not a procedural term but rather appears in doctrinal maxims, particularly those establishing the relationship between knowledge of terminology and competence in a discipline or field of law.
---
Common Confusion
IGNORARI, IGNORAMUS, and IGNORANTIA are three distinct Latin terms sharing a common root that are frequently encountered together in older legal texts and sometimes run together without clear distinction. Ignoramus is a first-person plural present tense form ("we do not know"), used as the grand jury endorsement formula. Ignorantia denotes ignorance as a condition or state — the basis for doctrines such as ignorantia juris non excusat. Ignorari is the passive infinitive form — "to be unknown" — and functions grammatically and doctrinally differently from both. Researchers encountering any of these terms in historical sources should not assume interchangeability; the specific form shapes the meaning of the maxim in which it appears.
---
Why It Matters in Research
Researchers are most likely to encounter ignorari not as a standalone entry but embedded within Latin maxims quoted in treatises, pleading manuals, and early judicial opinions. The most significant such maxim is the one preserved in Burrill: Ignoratis terminis artis, ignoratur et ars — "Where the terms of an art are unknown, the art itself is unknown also." This maxim, attributed to Coke's commentary on Littleton, was invoked in legal argument to stress the importance of precise legal vocabulary and to justify close attention to technical terms in interpretation.
In the Law Mind corpus, this means ignorari is a doorway term. Encountering it in a historical source almost always signals that the surrounding text is engaged with one of three topics: (1) the grand jury process and its Latin formulae, in which case the relevant operative term is usually ignoramus rather than ignorari itself; (2) the law of ignorance as a defense or excuse, in which case ignorantia and its doctrinal progeny are the primary research targets; or (3) a methodological or interpretive argument about legal language and the necessity of understanding technical terms before applying legal rules.
The term is also a calibration marker for source dating. Heavy use of ignorari and related Latin passive forms in running text — rather than as defined terms — is characteristic of legal writing before roughly the mid-nineteenth century. When American courts and treatise writers moved toward English-language formulation of common law principles, Latin infinitive constructions like ignorari largely disappeared from judicial usage, surviving mainly in quoted maxims. If you are dating an undated document or tracing the evolution of an argument across sources, the presence or absence of such constructions is useful evidence.
---
Historical Dictionary Support
Burrill and Anderson approach ignorari from different angles, and the divergence is instructive. Burrill presents ignorari in its precise grammatical sense — the passive infinitive form — and anchors it immediately to the Coke maxim, treating the term as a building block of legal Latin rather than as an independent doctrine. Anderson, by contrast, moves quickly from ignorari to ignoramus and then to the grand jury procedure, using the cluster of related terms as an occasion to explain the practical mechanics of the "not a true bill" endorsement. Anderson's approach reflects his dictionary's practical, American-practitioner orientation; Burrill's reflects his more scholarly, English common law foundation.
Neither source provides significant doctrinal elaboration of ignorari in isolation, which accurately reflects the term's status: it is grammatical and formulaic infrastructure, not a doctrine in its own right. Both sources agree implicitly that the term's importance lies in its family of related concepts rather than in any independent legal rule it expresses.
What neither historical dictionary addresses is the maxim's continued methodological relevance — the principle that legal terms must be mastered before legal rules can be applied. That idea migrated into Anglo-American jurisprudence in ways that do not always carry the Latin forward, making the connection between ignorari-based maxims and later English-language interpretive canons easy to miss.
---
Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Grand Jury; Ignorance of Law; Latin Maxims in Common Law
---