Definition
Tertia (Latin: "third" or "third part") is a term from old English and Scots law referring to a widow's right to one-third of her deceased husband's heritable property. The word functions as a shorthand for tertia pars — "the third part" — and is used interchangeably with dower in English legal contexts and with terce in Scots law. As a doctrinal matter, tertia designates the proportional share to which a surviving widow was legally entitled as a matter of right, not by testamentary grant.
Common Confusion
TERTIA, DOWER, and TERCE are closely related but not perfectly synonymous across jurisdictions and historical periods. Tertia is the Latin form common in formal legal writing and Scots-influenced sources. Dower is the dominant English common law term, though dower did not always equal exactly one-third across all historical periods and jurisdictions — the fraction could vary. Terce is the direct Scots vernacular rendering of tertia and refers specifically to the widow's one-third life interest in her husband's heritable estate under Scots law. Researchers should not assume that finding one term in a source implies the precise rules of another.
Why It Matters in Research
Tertia appears almost exclusively in Latin-form legal instruments, treatises, and records from medieval and early modern England and Scotland. Researchers working in Scottish legal history will encounter tertia as a precursor or synonym for terce — a right that had a distinct procedural life in Scots law, including formal processes for its assertion and valuation. In English materials, the term yields quickly to dower, and by the early modern period tertia largely disappears from English practice except in scholarly or antiquarian legal writing.
The primary research trap is assuming that tertia, dower, and terce are fully interchangeable across sources. A document using tertia in a Scots context invokes Scots feudal rules; the same word in an English common law document may be doing slightly different work. Corpus researchers should use tertia as a search term primarily for Latin-form instruments and pre-modern treatises, and pivot to dower or terce when working in vernacular records or jurisdiction-specific materials from the seventeenth century forward.
Note also that tertia pars — the full Latin phrase — may appear where tertia alone does not, and searches should account for both forms.
Historical Dictionary Support
Burrill's Law Dictionary treats tertia briefly but accurately, glossing it as "third; (third part, tertia pars;) dower" and placing it in both old English and Scotch law. Burrill's cross-reference to Spelman, to Craig's De Jure Feudali, and to Blackstone's Commentaries situates tertia within the feudal property tradition. Craig's work is particularly significant because it bridges Scottish and continental feudal doctrine, and tertia appears there as a term with recognized feudal pedigree rather than merely local custom. Blackstone's reference at 2 Bl. Com. 129 connects the term to the English dower framework without treating it as a term of art in active English practice — by Blackstone's time it was already receding into learned citation.
No significant divergence exists among the available historical sources on this term's meaning; the consensus is clear and narrow. What historical dictionaries understandably omit is the procedural distinctiveness of terce in Scots practice — the formal declarator of terce, valuation processes, and interactions with the feudal superior — which tertia as a bare Latin term does not capture.
Jurisdictional Note
Tertia as an operative legal term is primarily of Scots law significance, where its vernacular descendant terce remained a living doctrine well into the modern era. In English law, dower absorbed its function and tertia survives only in antiquarian and Latin-form sources. Researchers in Irish and colonial American records working with feudal land grants may encounter the term in Latin instruments but should not assume it carries Scots procedural content in those contexts.