Definition
An archaic term meaning "collateral," used exclusively in the context of lines of descent or relationship. Found in the phrase *en line biline* ("in the collateral line"), the word denotes a line of kinship running alongside the direct line — that is, through relatives who share a common ancestor with the subject but who are not in a direct ascending or descending relationship. The term appears in Britton, the 13th-century Anglo-Norman legal treatise, and has no meaningful life outside that source.
Common Language
Modern common usage (Wiktionary): Not recorded as a standard English word.
Historical common usage (Webster's 1913): Not recorded.
Burrill notes that the word is "essentially English" — a compound of "by" (side) and "line" — anglicized into the Anglo-Norman legal text. Despite its English roots, it never achieved currency in ordinary speech. The legal meaning is its only meaning.
Why It Matters in Research
This term is encountered almost exclusively when reading or researching Britton directly or secondary sources that quote Britton. Its significance is narrow but specific: it signals a discussion of collateral succession or collateral kinship, which in medieval inheritance law carried distinct consequences from lineal descent. Researchers tracing the historical development of inheritance rules, the law of descent, or the concept of collateral heirs should recognize *biline* as a marker pointing toward collateral-line analysis in a 13th-century English common-law context.
The practical trap is the term's obscurity. A researcher unfamiliar with the word encountering *en line biline* in a historical treatise or secondary commentary might misread it as a proper name, a scribal error, or a Latin term. It is none of these. It is a functional Anglo-Norman legal descriptor with an identifiable English etymology.
Note also that Black's 2nd Edition contains a minor typographical corruption of the phrase — rendering it *en line bdiline* — which could cause further confusion when comparing editions. The 1st Edition and Burrill's both carry the correct form: *en line biline*.
Historical Dictionary Support
The four historical sources are in close agreement, which is unsurprising given the term's narrow provenance. All four trace the word to the same passage in Britton (c. 119) and all four give the same essential definition: collateral.
Burrill's entry is the most analytically useful, offering the compound etymology ("by-line, side line") that explains why the word means what it means. This etymological gloss — absent from Black's and reduced to a single word in Bouvier's — is genuinely helpful for a researcher trying to understand the term rather than merely identify it.
Black's 1st and 2nd editions add nothing beyond Burrill except the minor textual discrepancy noted above. Bouvier's entry is the most stripped-down of the four, offering only the single-word gloss "Collateral" with no context.
None of the historical sources develop the substantive legal doctrine behind the term — the law of collateral inheritance itself — or explain how Britton's usage fit into the broader scheme of medieval succession. Researchers needing that doctrinal context must turn elsewhere.
Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Descent and Distribution (Historical); Collateral Kinship and Succession