LSJ
ὁ, chief of a τριττύς III, IG2². 641.31 (iii BC), Poll. 8.109; = tribunus, D.H. 2.7; of an officer in the army, Lib. Or. 25.58; τριττυάρχης, EM 768.13.
Liddell-Scott-Jones, Greek-English Lexicon (9th ed., 1940)
Pape
ὁ, Anführer, Vorsteher einer τριττύς, Poll.
Pape, Griechisch-deutsches Handwörterbuch (3. Aufl., 1914)