noun, masculine/pɛ̃.te.kɔ̃.taʁk/plural: pentécontarques
pentécontarque is masculine in French.
pentecontarch (the commander of a platoon of fifty men)
Related: pentécontarchie
From Latin pentēcontarchus, from Ancient Greek πεντηκόνταρχος (pentēkóntarkhos, literally “commander of fifty”).