Abbott-Smith Manual Greek Lexicon
κοσμοκράτωρ (G2888)
1 *† κοσμοκράτωρ , -ορος, ὁ ( κόσμος , κρατέω ), in Orphic hymns, al. (v. AR, Eph 6:12 ), a ruler of the whole world (and so in Rabbinic writings: קוֺזמוֺקְרָטוֺר ). a ruler of this world (in contrast to παντοκράτωρ ): οἱ κ. τ. σκότους τούτου , the rulers of this dark world , Eph 6:12 .†
G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922) — public domain