con·vul·sion / kənˈvəlshən/ • n. (often convulsions) a sudden, violent, irregular movement of a limb or of the body, caused by involuntary contraction of muscles and associated esp. with brain disorders such as epilepsy, the presence of certain toxins or other agents in the blood, or fever in children. ∎  (convulsions) uncontrollable laughter: the audience collapsed in convulsions. ∎  an earthquake or other violent or major movement of the earth's crust. ∎ fig. a violent social or political upheaval.

convulsion Intense, involuntary contraction of the muscles, sometimes accompanied by loss of consciousness. A seizure may indicate epilepsy although there are other causes, including intoxication, brain abscess or hypoglycaemia.

convulsion (kŏn-vul-shŏn) n. an involuntary contraction of the muscles producing contortion of the body and limbs. Rhythmic convulsions of the limbs are a feature of major epilepsy. febrile c. an epileptic-type seizure associated with a fever, which affects infants and young children and is usually caused by a viral infection.