hypomnesia vs syncope

hypomnesia

noun
  • deficiency of the memory 

syncope

noun
  • A loss of consciousness when someone faints. 

  • A missed beat or off-beat stress in music resulting in syncopation. 

  • The loss or elision of a sound, from the interior of a word, especially of a vowel sound with loss of a syllable. 

How often have the words hypomnesia and syncope occurred in a corpus of books? (source: Google Ngram Viewer )