exhalation vs exhaust system

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 

exhaust system

noun
  • The subsystem of an engine that takes the products of the combustion chamber through a catalytic converter and silencer to the exhaust pipe 

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