Tagmatarchis, in more archaic context transliterated as Tagmatarches (Greek: Ταγματάρχης, abbreviated as Τχης), anglicized as Tagmatarch, is used in the Greek language to mean "Major". More precisely, it means "commander of a tagma".
The rank dates to Antiquity and was also used in the Byzantine Empire. In the modern Hellenic Army, the rank is superior to a Lokhagos (captain) and inferior to an Antisyntagmatarchis (Lieutenant Colonel), and held either usually by battalion (tagma) executive officers (battalions are typically commanded by Lieutenant Colonels). In this case they are addressed as "Kyrie Ypodioikita" (Κύριε υποδιοικητά), or simply as "Kyrie Tagmatarcha" (Κύριε Ταγματάρχα) in other cases.
Rank insignia of a Tagmatarchis, 1908–1936
Rank insignia of a Tagmatarchis, 1936–1968
Current rank insignia of a Tagmatarchis, since 1975