Etymology tree Proto-Indo-European *ser-? Proto-Indo-European *srew- Proto-Indo-European *sru-dʰ-mo-s Proto-Hellenic *hrutʰmós Ancient Greek ῥῠθμός (rhŭthmós)bor. Latin rhythmusder. English rhythm First coined in 1557, from Latin rhythmus, from Ancient Greek ῥυθμός (rhuthmós, “any measured flow or movement, symmetry, rhythm”), from ῥέω (rhéō, “to flow, run, stream, gush”).