What is the term for words that imitate sounds, like 'buzz'?

The term for words that imitate sounds, like “buzz,” is onomatopoeia.

Onomatopoeic words echo, resemble, or suggest the sounds they describe. English examples include “meow,” “hiss,” “beep,” “clang,” “splash,” and “hiccup.” The word can function as a noun, verb, or interjection: a bee buzzes, a buzz is heard, and “buzz!” can represent the sound itself.

The term comes from Ancient Greek onomatopoiía, meaning “name-making,” from words meaning “name” and “making.” Although onomatopoeia seems to connect sound and meaning directly, it is shaped by each language’s sound system. A clock says “tick-tock” in English, but similar sounds are represented differently in Spanish, Mandarin, Japanese, and other languages.

Onomatopoeia is different from alliteration, which repeats initial sounds across nearby words, and from a simile, which compares two things using words such as “like” or “as.”