1. A speech form or an expression of a given language that is peculiar to itself grammatically or cannot be understood from the individual meanings of its elements, as in keep tabs on.
2. The specific grammatical, syntactic, and structural character of a given language.
3. Regional speech or dialect.
a. A specialized vocabulary used by a group of people; jargon.
b. A style or manner of expression peculiar to a given people.
5. A style of artistic expression characteristic of a particular individual, school, period, or medium.
[Late Latin idima, idimat-, from Greek, from idiousthai, to make one's own, from idios, own, personal, private; see s(w)e- in Indo-European roots.]
idiomatic, idiomatical | adj
idiomatically | adv
idiomaticalness | n