Strong's G4759 · Greek

στρατοπεδάρχης ου ὁ

stratopedarches · strat-op-ed-ar'-khace

from 4760 and 757; a ruler of an army, i.e. (specially), a Praetorian praefect

Scholarly Lexicons

Abbott-Smith Manual Greek Lexicon

 1 (KJV) *† στρατοπέδ-αρχος (Rec. -ης ), -ου, ὁ ( στρατόπεδον , ἄρχω ), a military commander , esp. the Pretorian prefect : Ac 28:16 (WH, om.).† 

G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922) — public domain