πεντηκόνταρχος
From LSJ
Ἀναξαγόρας δύο ἔλεγε διδασκαλίας εἶναι θανάτου, τόν τε πρὸ τοῦ γενέσθαι χρόνον καὶ τὸν ὕπνον → Anaxagoras used to say that we have two teachers for death: the time before we were born and sleep | Anaxagoras said that there are two rehearsals for death: the time before being born and sleep
English (LSJ)
ὁ, at Athens,
A commander of fifty men, serving under the τριήραρχος, X. Ath. 1.2, D.50.18, 19, 24 (wrongly expld. by Harp. as commander of a πεντηκόντερος). 2 generally, leader of a company of fifty, LXX Ex. 18.21, 4 Ki.1.9.