What do we call a word that mimics the sound it represents?

A word that mimics the sound it represents is referred to as onomatopoeia. This literary device involves using words that phonetically imitate or resemble the sound they describe, such as "buzz" for the sound a bee makes or "bang" for an explosion. Onomatopoeia is effectively used in poetry and prose to create vivid imagery and enhance the reader's experience by evoking the sensory experience of sound.

Idiom refers to a phrase or expression that has a figurative meaning rather than a literal one, which does not involve sound imitation. Alliteration is the repetition of the same initial consonant sounds in a sequence of words, often used for poetic effect but not related to sound mimicking. Symbolism involves using symbols to represent ideas or concepts, which again differs significantly from the concept of sound imitation inherent in onomatopoeia.