- 1. A sudden or violent disturbance in the mental or emotional faculties.
2. A state of profound depression of the vital processes of the body that is characterized by pallor, rapid but weak pulse, rapid and shallow respiration, reduced total blood volume, and low blood pressure and that is caused usually by severe especially crushing injuries, hemorrhage, burns, or major surgery.
3. Sudden stimulation of the nerves or convulsive contraction of the muscles that is caused by the discharge through the animal body of electricity from a charged source.
Definition from: Merriam-Webster's Medical Dictionary by Merriam-Webster Inc.
See also Understanding Medical Terminology.