Definition
Mora carries two distinct legal meanings depending on context and legal tradition.
1. (Civil law) Culpable delay or default in fulfilling a legal obligation. Mora denotes more than mere lateness — it is delay that carries legal consequence, typically because a duty was due, a demand has been made or was legally unnecessary, and the obligor has no valid excuse for non-performance. The classic application is delay in the payment of a debt or discharge of a contractual duty. The maxim Nulla intelligitur mora ibi fieri ubi nulla petitio est — no delay is understood where there is no demand — reflects the traditional requirement that a creditor's demand (interpellatio) was necessary to put a debtor in mora, though later civil law developments recognized exceptions where the obligation's terms or nature made demand unnecessary.
2. (Saxon/common law land terminology) A moor, marsh, heath, or boggy wasteland. In early English property law, mora referred to barren or unprofitable ground, including waterlogged terrain, that did not yield cultivable value. The compound Mora mussa designates a watery or boggy moor — effectively a morass.
Common Language
Modern common usage (Wiktionary): A finger-guessing game popular in Italy, in which players simultaneously extend fingers and call out a number, attempting to match the total shown.
Historical common usage (Webster's 1913): The same game of guessing the number of fingers extended in a quick movement of the hand, described as much played by Italians of the lower classes.
Neither common meaning has any relation to the legal term. Both legal senses of mora — civil-law default and Saxon land description — are purely technical and derive from Latin and Saxon roots entirely separate from the Italian game. A researcher encountering mora in a legal source should not carry any common-language connotation to the interpretation.
Common Confusion
The two legal meanings of mora are etymologically unrelated and serve entirely different research contexts. The civil-law mora (Latin: delay, default) appears in contract, debt, and obligation doctrine. The Saxon mora (barren ground) appears in property records, land grants, and early English real property law. Both appear in the same historical dictionaries under the same headword, and conflating them in either direction will mislead research. Context — civil law obligation versus land description — resolves the ambiguity in nearly every instance.
Mora should also be distinguished from related civil-law concepts: mora debitoris (delay attributable to the debtor) versus mora creditoris (delay attributable to the creditor who fails to accept performance). Each carries different legal consequences and the distinction matters in civilian jurisdictions.
Why It Matters in Research
The civil-law sense of mora is the meaning researchers will encounter most frequently in English-language legal sources, and its doctrinal content is richer than the brief dictionary entries suggest. Burrill's treatment is the most instructive among the shelf sources, noting that mora was "said to be of difficult definition" in the Digest — a signal that the concept carried nuance even in Roman law. Researchers working in contracts, commercial law, or comparative law should treat mora as a gateway to a broader cluster of civil-law obligation doctrine: the conditions that establish default, the consequences that flow from it (including liability for subsequent impossibility of performance and accrual of interest), and the distinction between debtor's and creditor's mora.
For historical English property research, the Saxon mora is relevant primarily to pre-modern land records, Domesday-era descriptions, and early common law materials treating wasteland, marsh rights, and commons. Coke on Littleton (Co. Litt. 5) and Fleta (lib. 2, c. 71) are the foundational sources.
Researchers using 19th-century American legal materials will encounter mora most often in treatises discussing civil-law influence on Louisiana, Quebec, or Spanish-derived property law, and in comparative contract scholarship. The maxim Mora reprobatur in lege — delay is reprobated in law (Jenk. Cent. p. 51, case 97) — appears in collections of legal maxims and can be cited in arguments about the general principle that law disfavors unjustified non-performance.
One research trap: because mora is a short Latin word with multiple unrelated meanings, keyword searches in digitized historical corpora will return noise across all senses. Filtering by surrounding terms (obligatio, debitor, creditor for the civil-law sense; heath, marsh, wasteland, moor for the property sense) will improve precision.
Historical Dictionary Support
The historical dictionaries are in agreement on both senses but unequal in their depth. Black's (1st and 2nd editions) and Bouvier provide skeletal definitions only. Burrill's is the standout, supplying the maxim on demand as a condition of mora, citing the Digest directly (Dig. 32.1.32 and Dig. 50.17.88), and acknowledging the concept's acknowledged difficulty of definition — a candor absent from the other sources.
All sources cross-reference In Mora, the adverbial phrase meaning "in default" or "in a state of culpable delay," which is the form most commonly encountered in legal instruments and judicial opinions. That entry should be consulted alongside this one.
The maxim Mora reprobatur in lege appears in both Black's 2nd edition and Burrill, attributed to Jenkin's Centuries. It functions as a general principle rather than a rule of decision, but its appearance in maxim collections means researchers will encounter it in early American and English legal argument.
None of the historical dictionaries develop the doctrine of mora creditoris — delay by the creditor — which is a meaningful gap for researchers in civilian or mixed legal systems.
Jurisdictional Note
The civil-law doctrine of mora remains operative in Louisiana, Quebec, Scotland, South Africa, and other civilian or mixed jurisdictions, where it has been developed by statute and case law beyond the Roman-law baseline. In common law jurisdictions, equivalent concepts travel under different labels — breach, repudiation, anticipatory breach — and mora as a technical term rarely appears in modern American or English case law outside of comparative or historical analysis.
Encyclopedia Cross-Reference
Law Mind Encyclopedia — Delay in Performance
Law Mind Encyclopedia — Civil Law Obligations
Law Mind Encyclopedia — Wasteland and Common Land (for the Saxon property sense)