Source : Webster's Revised Unabridged Dictionary (1913)

Portgreve \Port"greve`\, Portgrave \Port"grave`\, [AS.
   portger[=e]fa; port a harbor + ger[=e]fa a reeve or sheriff.
   See {Reeve} a steward, and cf. {Portreeve}.]
   In old English law, the chief magistrate of a port or
   maritime town.; a portreeve. [Obs.] --Fabyan.