The Collaborative International Dictionary
Thanage
Thanage \Than"age\, n. The district in which a thane anciently had jurisdiction; thanedom.
Douglas Harper's Etymology Dictionary
thanage
c.1400, from Anglo-French thaynage (c.1300), from English thane + Old French suffix -age (see -age).
Wiktionary
thanage
n. (context historical English) The district in which a thane has jurisdiction.