Onomatopoeia is the formation of a linguistic sign – typically a sound word – based on some similarity between the auditory character of the significans and some acoustic quality that is a salient component of the significatum. An onomatopoetic word is a word formed by onomatopoeia. An onomatopoetic word designates either a sound or something metonymically related to a sound.

English examples (from Corbett 1971: 491) include gong, crackle, and twitter. A noun like cuckoo designates a being that produces a sound like its significans.

Sound symbolism differs from onomatopoeia in not being confined to meanings related to a sound.