acidity vs pyrosis

acidity

noun
  • Excessive acid quality, as in gastric secretions. 

  • The quality or state of being acid. 

  • A caustic, sour, biting, or bitter quality. 

  • Sourness; tartness; sharpness to the taste. 

pyrosis

noun
  • A burning sensation in the chest due to reflux of stomach contents in the esophagus. 

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