clonus Syllabification: (clo·nus)Pronunciation: /ˈklōnəs/Definition of clonus noun Medicine muscular spasm involving repeated, often rhythmic, contractions. Derivatives clonicPronunciation: /ˈklänik/ adjective Origin: early 19th century: from Greek klonos 'turmoil'clonus in other Oxford dictionaries Definition of clonus in the British & World English dictionary