Source : Webster's Revised Unabridged Dictionary (1913)

Sunstroke \Sun"stroke`\, n. (Med.)
   Any affection produced by the action of the sun on some part
   of the body; especially, a sudden prostration of the physical
   powers, with symptoms resembling those of apoplexy,
   occasioned by exposure to excessive heat, and often
   terminating fatally; coup de soleil.

Source : WordNet®

sunstroke
     n : sudden prostration due to exposure to the sun or excessive
         heat [syn: {insolation}, {thermic fever}, {siriasis}]