Late Middle English; earliest use found in John Trevisa (c1342–?1402), translator. From post-classical Latin rhythmica branch of study that deals with rhythm, use as noun (short for ars rhythmica rhythmic art) of feminine of classical Latin rhythmicus. In form rythmice perhaps after post-classical Latin rhythmice from ancient Greek ῥυθμική, use as noun (short for ῥυθμικὴ τέχνη) of feminine of ῥυθμικός.