idiom

noun

1. a manner of speaking that is natural to native speakers of a language

   noun.communication

   Synonyms parlance

   Source: WordNet 3.0

2. the usage or vocabulary that is characteristic of a specific group of people

   noun.communication

   Synonyms accent dialect

   Source: WordNet 3.0

3. the style of a particular artist or school or movement

   noun.attribute

   Examples

   An imaginative orchestral idiom.

   Synonyms artistic style

   Source: WordNet 3.0

4. an expression whose meanings cannot be inferred from the meanings of the words that make it up

   noun.communication

   Synonyms idiomatic expression phrasal idiom phrase set phrase

   Source: WordNet 3.0

5. The syntactical or structural form peculiar to any language; the genius or cast of a language.

   noun

   Source: webster1913