Definition
Jequitas is a Latin term from the civil law tradition meaning equity — the principle of fairness and natural justice applied to soften the rigidity of strict legal rules. It stands in deliberate contrast to strictum jus or summum jus, the strict or extreme application of the law, which might produce technically correct but substantively unjust outcomes. The term is functionally equivalent to the more familiar aequitas and appears alongside related formulations including aequum, aequum bonum, aequum et bonum, and aequum et justum — all of which express the same core idea: that law ought to conform to what is fair, good, and just, not merely what is formally prescribed.
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Common Confusion
Jequitas, aequitas, and the phrase aequum et bonum are effectively interchangeable in the civil law sources, though aequitas is the far more common form and the one that dominates both the Digest and subsequent learned commentary. Researchers encountering jequitas in a historical text should not treat it as a distinct or specialized concept; it is a variant rendering of the same equity principle. The spelling variation likely reflects transcription conventions or regional Latin usage rather than any substantive doctrinal distinction.
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Why It Matters in Research
This term will appear only in older civil law materials, glossaries, and legal dictionaries operating in the civilian tradition. It is not a term of art in common law jurisdictions and does not appear in modern legal usage. Researchers will encounter it primarily when working through Latin maxims, early civil law commentaries, or historical dictionaries that catalog Roman and canon law vocabulary.
The key research trap is treating jequitas as a freestanding concept with its own doctrinal history. It does not have one. It is a lexicographical variant, and the substantive research trail leads immediately to aequitas — the term with developed civil law doctrine, extensive treatment in the Digest and Institutes, and a robust secondary literature. Any research question that begins with jequitas should pivot quickly to aequitas and to the broader tension between equity and strict law in the Roman tradition.
The opposing term, strictum jus (also summum jus), is equally important to understand. The phrase summum jus, summa injuria — extreme law is extreme injustice — captures the animating concern that jequitas and aequitas were developed to address. Researchers tracing the intellectual history of equity as a corrective to rigid legal rules will find this conceptual pairing foundational.
Black's citation to Calvin (Lexicon Juridicum) places this term in the tradition of early modern civilian reference works. Johann Kahl's Lexicon Juridicum Juris Caesarei simul et Canonici (commonly cited as Calvin or Calvinus) was a standard reference for Latin legal terminology in the sixteenth and seventeenth centuries and remains a useful source for tracing how civil law terms were understood by early modern jurists and commentators.
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Historical Dictionary Support
Black's Law Dictionary (2nd Ed., Supplemental) provides the only dictionary treatment identified for this specific spelling. The entry is brief: it defines jequitas as the civil law's equity, opposed to strictum or summum jus, and cross-references the synonymous formulations aequum, aequum bonum, aequum et bonum, and aequum et justum. The citation to Calvin confirms that this is a term sourced from the learned civilian lexicographic tradition rather than from case law or statute.
No treatment of jequitas as a distinct entry appears in the standard common law dictionaries, which is consistent with the term's purely civil law character. The substantive doctrine underlying the concept is covered extensively under aequitas in civilian-oriented sources. The historical dictionaries are in agreement on the meaning; there is no divergence worth noting. What the dictionaries collectively miss is any discussion of why this particular spelling variant existed or how widely it circulated — a gap that limits the term's usefulness as a research anchor but does not affect the underlying legal concept it describes.
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Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Aequitas; Equity in the Civil Law Tradition; Strictum Jus
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