amnesia /(ăm*nē"zhŭ or ăm*nē"zĭ*ȧ)/

am·ne·si·a

amnesia

n.
  1. Forgetfulness; loss of long-term memory. (Med.)
  2. A defect of speech, from cerebral disease, in which the patient substitutes wrong words or names in the place of those he wishes to employ. (Med.) [Obs.]