Definition
A Latin maxim meaning "according to custom." Ex more denotes that a practice, act, or obligation derives its authority or validity from established custom or usage rather than from formal written law, statute, or express agreement. In legal contexts, the phrase signals that the rule or conduct in question is grounded in long-standing practice recognized as binding or authoritative within a given community or legal system.
Why It Matters in Research
Ex more appears almost exclusively in older Latin maxim collections and civil law commentaries. Researchers encountering this phrase in historical sources should treat it as a marker pointing toward customary law arguments — a category of legal authority that carried significant weight in pre-codification common law and in civil law jurisdictions but that modern practitioners rarely invoke by name.
The phrase is most likely to surface in older treatises, ecclesiastical law sources, and early equity materials where custom was formally pleaded or argued as a source of right. In those contexts, distinguishing ex more from lex scripta (written law) was not merely stylistic — it was a substantive claim about the source and therefore the durability of the obligation.
Researchers should also note the company this maxim keeps. Historical dictionaries consistently cite ex more immediately adjacent to the maxim Ex multitudine signorum, colligitur identitas vera ("from a great number of signs or marks, true identity is gathered"). These two phrases appear together in Black's, Burrill, and Rapalje & Lawrence, which suggests they were transmitted together through shared source material — likely Calvin's Lexicon Juridicum — rather than curated independently. A researcher finding one phrase in a primary source document should search for the other, as their co-appearance may signal a common drafting lineage or a shared rhetorical tradition in the document under study.
This term has no significant modern litigation footprint. Its research value is almost entirely interpretive and historical: understanding what an older court, treatise writer, or pleader meant when they grounded a claim "according to custom."
Historical Dictionary Support
All four source dictionaries give identical or near-identical translations: "according to custom." The uniformity across Black's (1st and 2nd editions), Rapalje & Lawrence, and Burrill confirms this is a settled maxim with no contested meaning in the legal dictionary tradition. Burrill adds the most context, drawing on Calvin's Lexicon Juridicum as the root authority and pairing the phrase with explanatory commentary on the neighboring maxim about identity through accumulated signs. Black's 2nd edition follows Burrill closely. Rapalje & Lawrence is the most compressed, offering translation only.
None of the historical sources explain how ex more functioned procedurally — that is, how custom was pleaded, proven, or challenged in court. That gap is significant. Researchers who need to understand the evidentiary and procedural mechanics of custom as a legal source will need to look beyond dictionary entries to treatises on customary law and early common law pleading.