Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.
PORTMAN
As described in historical dictionaries
Patronymica Britannica (1860)
PORTMAN. A civic officer,'with duties similar to those of a modern mayor. The courts of this functionary were formerly called iJoHmannimotc!:. Portreeve is synonymous. The family of this name in Somersetshire, appear to have been eminent so early as the reign of Edward I. See Burke's Extinct Baronets.
Surname type: Occupational name
Origin: English
Region of origin: British Isles
Country of origin: England
Religion of origin: Christian
Language of origin: English