From Middle Frenchidiome, and its source, Late Latinidioma, from Ancient Greekἰδίωμα(idíōma, “a peculiarity, property, a peculiar phraseology, idiom”), from ἰδιοῦσθαι(idioûsthai, “to make one's own, appropriate to oneself”), from ἴδιος(ídios, “one's own, pertaining to oneself, private, personal, peculiar, separate”).