Idiom Definition & Meaning | Dictionary.com
https://www.dictionary.com/browse/idiomIdiom definition, an expression whose meaning is not predictable from the usual meanings of its constituent elements, as kick the bucket or hang one's head, or from the general grammatical rules of a language, as the table round for the round table, and that is not a constituent of a larger expression of like characteristics. See more.
Idiom - Wikipedia
https://en.wikipedia.org/wiki/IdiomAn idiom is a phrase or expression that typically presents a figurative, non-literal meaning attached to the phrase; but some phrases become figurative idioms while retaining the literal meaning of the phrase. Categorized as formulaic language, an idiom's figurative meaning is different from the literal meaning. Idioms occur frequently in all languages; in English alone there are an estimated twenty-five thousand idiomatic expressions.