n. [ OE. poplexye, LL. poplexia, apoplexia, fr. Gr. 'apoplhxi`a, fr. 'apoplh`ssein to cripple by a stroke; 'apo` from + plh`ssein to strike: cf. F. apoplexie. See Plague. ] (Med.) Sudden diminution or loss of consciousness, sensation, and voluntary motion, usually caused by pressure on the brain. [ 1913 Webster ]

☞ The term is now usually limited to cerebral apoplexy, or loss of consciousness due to effusion of blood or other lesion within the substance of the brain; but it is sometimes extended to denote an effusion of blood into the substance of any organ; as, apoplexy of the lung. [ 1913 Webster ]