Why It Matters in Research
Researchers encountering this term will almost certainly find it only in historical sources dealing with feudal tenure, manorial law, or early English common law. Its appearance in Black's, Bouvier's, and Black's 2nd is perfunctory — all three entries reduce to a single line attributed to Jacob's Law Dictionary (Giles Jacob, *A New Law-Dictionary*, various editions from 1729 onward). This daisy-chain attribution means the term's definition has never been independently verified or expanded by subsequent American or English legal lexicographers; each dictionary simply repeated Jacob.
For corpus research purposes: if this word appears in a document, the document is almost certainly pre-19th century and likely of English rather than American origin. It would appear in the context of feudal obligations, grants of land, or descriptions of hierarchical social and legal relationships. Do not mistake it for a personal surname (its only modern meaning) when encountered in a legal text.
Historical Dictionary Support
All three shelf sources — Black's (1st and 2nd editions) and Bouvier's — are in complete agreement and are identically terse: "A great lord. Jacob." No source elaborates on the term's legal significance, its use in specific legal contexts, or its relationship to comparable feudal designations. The uniformity suggests none of the editors had independent knowledge of the term's use in practice; all deferred entirely to Jacob. This is a terminal entry: the historical dictionaries give you nothing beyond the bare gloss, and no further synthesis is possible from these sources alone. A researcher needing more would need to consult Jacob's original dictionary directly or turn to primary sources in medieval and early modern English law.