clonus

noun

clo·​nus ˈklō-nəs 

: a rapid succession of alternating contractions and partial relaxations of a muscle occurring in some nervous diseases

clonic

ˈklä-nik 

adjective

clonicity

klō-ˈni-sə-tē 

klä-

noun

Word History

Etymology

borrowed from New Latin, borrowed from Greek klónos "chaotic throng, press (as of warriors in battle), physiological commotion (in the bowels)," perhaps from *kl-, zero grade of the Indo-European verbal base *kelh₁- "set in motion" + -onos, noun suffix — more at accelerate

Note: The Indo-European etymon *kelh₁- "set in motion" is based on I. Seržant, "Die idg. Wurzeln *kel₁- 'etw. bewegen' und *kelh₃- 'sich erheben'," Indogermanische Forschungen, Band 113 (2008), pp. 59-75. This etymology of klónos is supported by P. Chantraine (Dictionnaire étymologique de la langue grecque) and Lexikon der indogermanische Verben (2nd edition, p. 348), though the latter operates with a root *kel- "drive, urge" (antreiben) and actually takes klónos as evidence that *kel- did not have a following laryngeal. R. Beekes (Greek Etymological Dictionary), on the other hand, is skeptical of any connection with such a root. The only exactly parallel derivative appears to be thrónos "seat, throne entry 1," the etymology of which is also doubtful.

First Known Use

1817, in the meaning defined above

Medical Definition

clonus

noun

clo·​nus ˈklō-nəs 

: a series of alternating contractions and partial relaxations of a muscle that in some diseases of the central nervous system occurs in the form of convulsive spasms involving complex groups of muscles and is believed to result from alteration of the normal pattern of motor neuron discharge compare tonus sense 2