The Collaborative International Dictionary of English v.0.48:
Thessalonian \Thes`sa*lo"ni*an\, a. Of or pertaining to Thessalonica, a city of Macedonia. -- n. A native or inhabitant of Thessalonica. [1913 Webster]WordNet (r) 3.0 (2006):
Thessalonian n 1: a native or inhabitant of Thessalonica