exhalation vs secretion

exhalation

noun
  • That which is exhaled, or which rises in the form of vapor, fume, or steam 

  • A bright phenomenon; a meteor. 

  • The act or process of exhaling; breathing out 

secretion

noun
  • any substance that is secreted by an organism 

  • the act of secreting a substance, especially from a gland 

  • the act of hiding something 

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