Clonus

имя существительное [медицина] клонус, мышечное сокращение

Большой англо-русский словарь

Clonus

noun Etymology: New Latin, from Greek klonos agitation — more at hold a rapid succession of alternating contractions and partial relaxations of a muscle occurring in some nervous diseases • clonic adjectiveclonicity noun

Merriam-Webster's Collegiate Dictionary