cistern vs exhaust pipe

cistern

noun
  • The vessel surrounding the condenser in a steam engine. 

  • In a flush toilet, the container in which the water used for flushing is held; a toilet tank. 

  • A cisterna. 

  • A reservoir or tank for holding water, especially for catching and holding rainwater for later use. 

exhaust pipe

noun
  • On a steam locomotive, a pipe which takes away steam exhausted from a cylinder. 

  • For internal combustion engines, the pipe that vents waste gases from the engine. 

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