idiom -
n. 1 a group of words established by usage and having a meaning not deducible from those of the
individual words (as in over the moon, see the light).
2 a form of expression peculiar to a language, person, or group of people.
3 a the language of a
people or country. b the specific
character of this.
4 a characteristic mode of expression in music, art, etc.
[F idiome or LL idioma f. Gk idioma -matos private property f. idios own, private] 
