|a screen or mat covered with a dark material for shielding a camera lens from excess light or glare.|
|a calculus or concretion found in the stomach or intestines of certain animals, esp. ruminants, formerly reputed to be an effective remedy for poison.|
convulsion con·vul·sion (kən-vŭl'shən)
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.
Learn more about convulsion with a free trial on Britannica.com.