Definition
A Latin term from the civil law tradition carrying two related but distinct meanings:
1. To overflow or flood, as a river overflows its banks. Used in texts dealing with natural events and their legal consequences — particularly in contexts involving watercourses, boundaries, and liability arising from flooding.
2. To be superfluous or unnecessary; to contain more than is required. In the drafting and interpretation of legal instruments, abundare describes language or provisions that exceed what is strictly needed without, for that reason alone, being fatally defective. The maxim Non solent quæ abundant vitiare scripturas — superfluous matters do not usually vitiate writings — captures the operative legal principle: surplus language does not invalidate an instrument.
Common Confusion
Burrill notes that the civilian jurist Calvin distinguished abundare from redundare. Though both suggest excess, redundare carries the sense of flowing back or returning — a more active surplus — while abundare suggests simply being more than full. The distinction rarely surfaces in common-law research but may matter when reading civilian commentaries closely.
Why It Matters in Research
Researchers are most likely to encounter abundare in one of two contexts, and conflating them produces misreadings.
In texts on watercourses and natural events, abundare describes physical overflow — a river flooding its channel. The Digest passage (Dig. 2.11.2.8) situates the term in procedural discussion, not water law proper, so researchers following that citation should be alert to context.
The more jurisprudentially significant use is in instrument construction. The principle that surplus language does not vitiate a writing (Dig. 50.17.94) fed directly into common-law canons of construction that persist in modern contract and will interpretation. When researching those canons in historical sources, abundare and its associated maxim are the civil law anchor. Tracing how early English equity and common-law courts absorbed this civilian principle — often without citing the Latin term — requires recognizing that the underlying idea derives from this tradition.
Researchers using historical dictionaries should note that abundare appears infrequently in English-language legal texts precisely because the concept migrated into English law as a canon of construction rather than as a borrowed term. The Latin drops out; the rule stays.
Historical Dictionary Support
Burrill's Law Dictionary is the primary shelf source for this term in the Law Mind corpus and provides the essential civilian grounding. Burrill identifies both meanings, supplies the Digest citations, and flags the Calvin distinction between abundare and redundare — a useful pointer for researchers working in civilian sources but not one that Burrill develops further.
The term does not appear in common-law dictionaries of the same period (Bouvier, Black's early editions) under this heading, which itself is instructive: the concept traveled into Anglo-American law through maxim and canon rather than through direct adoption of the terminology. Historical sources that might be expected to carry abundare often subsume it under discussion of surplusage or the maxim utile per inutile non vitiatur (the useful is not vitiated by the useless), a related but not identical principle.
Researchers should not assume that the absence of abundare from a common-law dictionary means the underlying rule was unknown — it was well-known, just not labeled by this name.