What is an idiom?

An idiom is indeed defined as an expression that has a figurative meaning different from its literal meaning. This means that the words that make up the idiom do not directly convey the overall meaning when taken at face value. For example, the phrase "kick the bucket" is an idiom that figuratively means to die, which is not evident if one interprets the words literally. Idioms are often culturally specific and may not translate well into other languages, reflecting the unique linguistic identity of a group.

The other definitions listed do not accurately capture the essence of an idiom. While one option mentions a word with multiple meanings, this refers to polysemy rather than idiomatic expressions. The mention of synonyms relates to words that have similar meanings and does not pertain to idioms. Lastly, the idea of a narrative style using poetic language relates to styles of writing rather than the specific concept of idiomatic expressions. Thus, the correct answer encapsulates the essence of idioms as figurative expressions that convey meanings not deducible from their individual components.