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.". "It is that within us that makes for righteousness."." "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.
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