idiom

Etymology

From Middle French idiome, and its source, Late Latin idioma, from Ancient Greek ἰδίωμα (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”).

noun

1. A manner of speaking, a mode of expression peculiar to a language, language family, or group of people.
   In English, idiom requires the indefinite article in a phrase such as "she's an engineer", whereas in Spanish, idiom forbids it.
   Some of the usage prescriptions improved clarity and were kept; others that yielded discordant violations of idiom were eventually revised.
   1. (programming) A programming construct or phraseology that is characteristic of the language.
      I have to use the same assignment and call to raw_input in two places. How can I avoid that? I can use the while True/break idiom: […] 2005, Magnus Lie Hetland, Beginning Python: From Novice to Professional, page 100
2. A language or language variety; specifically, a restricted dialect used in a given historical period, context etc.
   In the idiom of the day, they were sutlers, although today they'd probably be called vendors.
   Many parents and teachers have become irritated to the point of distraction at the way the weed-style growth of "like" has spread through the idiom of the young. 13 Jan 2010, Christopher Hitchens, “The Other L-Word”, in Vanity Fair
3. An established phrasal expression whose meaning may not be deducible from the literal meanings of its component words.
   She often spoke in idioms, pining for salad days and complaining about pots calling the kettle black.
   You’re history, we say […]. Surely it is an American idiom. Impossible to imagine a postwar European saying, “You’re history. . . . That’s history,” meaning fuhgeddaboudit, pal. 2008, Patricia Hampl, “You’re History”, in Patricia Hampl, Elaine Tyler May, editors, Tell Me True: Memoir, History, and Writing a Life, Minnesota Historical Society, page 134
4. An artistic style (for example, in art, architecture, or music); an instance of such a style.
   the idiom of the expressionists