Definition
Rhetorical figures are the named, recurring patterns that constitute style — the third of the five rhetorical canons. The classical tradition divides them into two large families. Schemes are deviations from ordinary word-order or syntax (anaphora, parallelism, chiasmus, asyndeton). Tropes are deviations from ordinary word-meaning (metaphor, simile, metonymy, synecdoche, irony, hyperbole). The Renaissance handbooks listed several hundred named figures; a working modern vocabulary needs perhaps twenty.
A figure is not decoration. It is a structural device that does cognitive work: anaphora ('we shall fight on the beaches, we shall fight on the landing grounds') drills a refrain into memory; antithesis ('ask not what your country can do for you, ask what you can do for your country') makes a moral point feel inescapable by binding its two halves into one shape; metaphor smuggles a whole frame of inference into a single word.
Why it matters
How it works
Figures cluster by function. Memory-aids (anaphora, epistrophe, parallelism) make a phrase stick. Antithetical figures (antithesis, chiasmus) sharpen a moral choice into binary form. Tropes of substitution (metonymy, synecdoche) compress relationships into shorthand ('the Crown', 'Washington', 'boots on the ground'). Metaphor — the master trope — imports a whole inferential structure from one domain into another, often invisibly.
Modern speechwriting still leans on the same handful. Listen to any successful political speech and you will hear anaphora and antithesis within the first minute. Listen to an advertisement and you will count metaphors per second. Knowing the names converts admiration into analysis.