What do you call an expression that conveys a meaning different from its verbatim interpretation?

An expression that conveys a meaning different from its verbatim interpretation is referred to as an idiom. Idioms are phrases where the meanings cannot be deduced from the individual words. For example, the idiom "kick the bucket" does not mean to literally kick a bucket; rather, it means to die. This characteristic of idioms makes them unique and culturally specific, often adding depth and color to language.

Other options like proverbs, metaphors, and similes serve different functions. Proverbs typically deliver wisdom or a moral lesson in a succinct manner, and are also culturally specific. Metaphors are direct comparisons between two unrelated things, suggesting that one thing is another, while similes use "like" or "as" for comparison. Both metaphors and similes enhance descriptions but don’t necessarily operate on the premise of a hidden or non-literal meaning in the same way idioms do. Hence, the focus on idioms as expressions with meanings beyond their literal words makes it the correct choice in this context.