Idiom
Idiom (id"i*um) , noun
[French idiome, Latin idioma, from Greek 'idi`wma, from 'idioy^n to make a person's own, to make proper or peculiar; from 'i`dios one's own, proper, peculiar; prob. akin to the reflexive pronoun o"y^, o'i^, 'e`, and to "eo`s, 'o`s, one's own, Latin suus, and to English so.]
1.
The syntactical or structural form peculiar to any language; the genius or cast of a language.
Idiom may be employed loosely and figuratively as a synonym of language or dialect, but in its proper sense it signifies the totality of the general rules of construction which characterize the syntax of a particular language and distinguish it from other tongues.
By idiom is meant the use of words which is peculiar to a particular language.
He followed their language [the Latin], but did not comply with the idiom of ours.
2.
An expression conforming or appropriate to the peculiar structural form of a language.
Some that with care true eloquence shall teach,
And to just idioms fix our doubtful speech.
3.
A combination of words having a meaning peculiar to itself and not predictable as a combination of the meanings of the individual words, but sanctioned by usage; as, an idiomatic expression; less commonly, a single word used in a peculiar sense.
It is not by means of rules that such idioms as the following are made current: “I can make nothing of it.” “He treats his subject home.” Dryden. “It is that within us that makes for righteousness.” M. Arnold.
Sometimes we identify the words with the object -- though by courtesy of idiom rather than in strict propriety of language.
4.
The phrase forms peculiar to a particular author; as, written in his own idiom.
Every good writer has much idiom.
5.
Dialect; a variant form of a language.