Which term describes a word or phrase that has a meaning different from its literal interpretation?

An idiom is a phrase or expression that has a figurative meaning that differs from its literal interpretation. For example, when someone says "kick the bucket," it doesn't mean someone is literally kicking a bucket; instead, it is an idiomatic expression meaning that someone has died. Idioms often arise from cultural context and don’t make sense when taken word for word, which is what distinguishes them from other forms of expression like metaphors or similes.

Metaphors, while they do imply a meaning beyond the literal, typically create a direct comparison between two unlike things without using "like" or "as." Similes, similarly, make comparisons between two different things but do so explicitly using "like" or "as." Hyperbole involves exaggerated statements not meant to be taken literally, often for emphasis, but it does not convey a different meaning in the same way that idioms do. Therefore, the term that accurately fits the description given in the question is idiom.