Where does “អេកូស” come from?

អេកូស (Khmer) comes from French Écosse, from Middle French Escosse, from Old French Escoce, from Latin Scotia, from Ancient Greek σκοτία, from Ancient Greek σκότος, from Proto-Indo-European skh₃tos, from Proto-Indo-European (s)ḱeh₃- — darkness, shadow.