Definition
Hydage is an alternative spelling of hidage — a form of land tax assessed in medieval England based on the hide, a unit of land area. The term has no independent legal content distinct from hidage; all substantive doctrine, historical context, and research guidance applies to that entry.
Common Language
Modern common usage (Wiktionary): Alternative form of hidage.
Historical common usage (Webster's 1913): A land tax. See Hidage.
The term is an archaic variant with no presence in ordinary modern English. No meaningful gap between common and legal usage exists because the word does not appear in modern common usage at all.
Why It Matters in Research
Researchers encountering "hydage" in historical sources should treat it as a direct orthographic variant of hidage and consult that entry for full analysis. Spelling inconsistency is characteristic of medieval and early modern legal records, where Latin, Norman French, and vernacular English forms competed and scribal practice was not standardized. A corpus search limited to one spelling will miss occurrences under the other. Both forms appear in historical legal dictionaries, with the weight of authority directing readers from hydage to hidage without elaboration.
Historical Dictionary Support
All four source dictionaries — Black's (1st and 2nd editions), Rapalje & Lawrence, and Burrill — treat hydage as a cross-reference to hidage and supply no independent definition. Webster's 1913 offers the only gloss at this spelling ("a land tax"), confirming the meaning while pointing to hidage for detail. The Rapalje & Lawrence entry as reproduced appears to contain a textual artifact: it appends language concerning hypothecation of goods and a captain's right to hypothecate a vessel for repairs, which plainly belongs to a different entry and should not be associated with hydage. Researchers relying on that source should treat the appended hypothecation language as a misattribution or scanning error.