Definition
"Fortiori" does not function as a standalone legal term. It appears exclusively as part of the Latin phrase A FORTIORI, meaning "with stronger reason" or "all the more so." The phrase is used in legal reasoning to indicate that if one proposition is true, a related but stronger proposition must also be true — because the reasoning that supports the first applies even more forcefully to the second.
See: A FORTIORI.
Common Confusion
"Fortiori" is sometimes mistakenly treated as a complete term when encountered in truncated indexes, footnotes, or older print digests that dropped the leading "a." It is not a standalone concept. Similarly, FORTIS — the Latin adjective meaning strong, appearing in pleading and admiralty phrases — shares the same Latin root but is entirely unrelated in meaning and legal use. Do not conflate them.
Why It Matters in Research
Researchers encountering "fortiori" in historical legal texts, digests, or indexes are looking at a fragment of the phrase A FORTIORI. The term has no independent legal meaning and will not appear in full form in operative legal text — only as a pointer. All three historical dictionary sources confirm this by redirecting immediately to A FORTIORI without elaboration.
When searching Law Mind corpus sources, query A FORTIORI as the full phrase. Index entries, digest headings, and cross-references in older materials sometimes list the term under "fortiori" alone as a shorthand, but the substantive content is always found under the complete phrase.
Historical Dictionary Support
All three sources — Black's Law Dictionary (both editions) and Bouvier's — treat this entry identically: a bare redirect to A FORTIORI. Bouvier adds a note on the unrelated Latin term FORTIS (strong), which shares a root but carries no legal overlap with A FORTIORI. The inclusion of FORTIS in Bouvier's entry is a function of alphabetical proximity, not conceptual connection. Researchers should not read any relationship between FORTIS (or the Latin phrase FORTIS ET SANA, used in admiralty and pleading contexts to describe a vessel as staunch and strong) and the logical phrase A FORTIORI.