What term describes the formation of a word by imitating a sound associated with its referent?

The term that describes the formation of a word by imitating a sound associated with its referent is onomatopoeia. Onomatopoeia occurs when a word phonetically resembles or suggests the sound that it describes, such as "buzz" for the sound a bee makes, or "clang" for the sound of metal striking metal. This sound-symbolic quality gives onomatopoeic words a vividness and immediacy that enhances the imagery in writing.

Alliteration refers to the repetition of initial consonant sounds in closely placed words, which contributes to the rhythm and musicality of language but does not specifically imitate sounds. Assonance involves the repetition of vowel sounds within closely placed words; like alliteration, this enhances the auditory quality of language but is not sound imitative. Consonance also involves the repetition of consonant sounds, typically at the end or in the middle of words, but similarly lacks the direct association with imitating sounds. Each of these terms serves a different purpose in the realm of sound devices in poetry and prose, but onomatopoeia uniquely captures the essence of mimicking real-world sounds.