1580s, from Latin convulsionem (nominative convulsio), noun of action from past participle stem of convellere "to tear loose," from com- "together" (see com-) + vellere "to pluck, pull violently."
convulsion con·vul·sion (kən-vŭl'shən)
n.
An intense, paroxysmal, involuntary muscular contraction.
A severe, often violent involuntary contraction of the muscles. Convulsions may be caused by high fevers or poisoning and often accompany such diseases such as epilepsy.
condition characterized by violent, uncontrolled spasmodic contractions and relaxations of the voluntary muscles. Convulsions may be a symptom resulting from various conditions and diseases, such as epilepsy, uremia, eclampsia, rabies, tetanus, strychnine poisoning, and cerebral tumour. They are usually accompanied by loss of consciousness. During a convulsion the individual's clothing should be loosened around the neck, the head should be cushioned with a pillow, and any sharp or hard objects should be removed from the area. An object should never be inserted into the person's mouth during a convulsion. Medical treatment should be sought immediately after the convulsion ceases.