convulsion (n.)youdaoicibaDictYouDict[convulsion 词源字典]
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" (see svelte).[convulsion etymology, convulsion origin, 英语词源]