Thegen

The Thegen was a common title for a Chieftain among the Northmen.Among the Rohirrim the equivalent Thane designated a follower or squire while among the Hobbits the Thain designated the nominal leader of the Shirefolk and head of the Took-clan.Among the Woodmen the Thius or later Degan was the nominal Chieftain of the Woodmen of Rhovanion who traditionally resided at Theihstathbaurg.

speculations
The older ICE Sourcebooks use the terms Thyn and Thign.While Thyn is an incorrect form,the word thign derives from anglo-saxon þegen, old frankish degan and Old Norse þegn'', all words meaning a free man, Hero, Warrior, servant, thane.