A figure of speech is the use of a word or words diverging from its usual meaning. It can also be a special repetition, arrangement or omission of words with literal meaning, or a phrase with a specialized meaning not based on the literal meaning of the words in it, as in idiom, metaphor, simile, hyperbole, or personification. Figures of speech often provide emphasis, freshness of expression, or clarity. However, clarity may also suffer from their use, as any figure of speech introduces an ambiguity between literal and figurative interpretation. A figure of speech is sometimes called a rhetorical figure or a locution.

Not all theories of meaning have a concept of "literal language" (see literal and figurative language). Under theories that do not, figure of speech is not an entirely coherent concept.

Rhetoric originated as the study of the ways in which a source text can be transformed to suit the goals of the person reusing the material. For this goal, classical rhetoric detected four fundamental operations that can be used to transform a sentence or a larger portion of a text: expansion, abridgement, switching, and transferring.