What does the term 'idiom' refer to?

The term 'idiom' refers to a common, often used expression that has a figurative meaning that is different from the literal meanings of the individual words within the expression. For example, the phrase "kick the bucket" does not refer to physically kicking a bucket but rather means to die. Idioms are culturally specific and can convey meanings that are deeply embedded in the language and typically understood by native speakers.

In contrast, a type of metaphor refers to a broader category of figurative language rather than a specific expression. A specific grammatical structure does not accurately capture what idioms are, as idioms are more about the use of language in specific contexts rather than strict grammatical rules. Similarly, while literary devices for rhyme involve the sound and rhythm of words, idioms focus on figurative meaning rather than phonetic properties. Thus, 'B' accurately captures the essence of what an idiom is.