Etymology
Borrowed from Greek αρματολός (armatolós), alternative form of αρματόλογος (armatólogos, “a person concerned or involved with arms or weapons”), from άρματα (ármata) (plural of άρμα (árma, “weapon”), from Byzantine Greek ἄρμα (árma), from Latin arma (“armour, defensive arms, shields, weapons of war”), from Proto-Indo-European *h₂(e)rmos (“fitting”), from Proto-Indo-European *h₂er- (“to join”)) + λόγος (lógos, “subject matter”) (from Ancient Greek λόγος (lógos), from λέγω (légō, “to say”), from Proto-Indo-European *leǵ-).
The plural form armatoloi and possibly armatoli are from the Greek plural form αρματολοί (armatoloí).