noun

• (chiefly psychology, uncountable) The phenomenon of the reappearance of a long-forgotten memory as if it were a new experience; (countable) an instance of this. Contrast cryptaesthesia.
  "All the witnesses of Mlle. [Hélène] Smith's Hindoo somnambulisms who are of the same opinion on that subject (several refrain from having any) unite in seeing in it a curious phenomenon of cryptomnesia, of reappearances of memories profoundly buried beneath the normal waking state, together with an indeterminate amount of imaginative exaggeration upon the canvas of actual facts. But by this name of cryptomnesia or resurrection of latent memories, two singularly different things are understood."