jalousie vs vacuum tube

jalousie

noun
  • A component in a ventilation system. 

  • A pastry with the upper side sliced before final baking to resemble a wooden slatted blind. 

  • Upward sloping window slats which form a blind or shutter, allowing light and air in but excluding rain and direct sun. 

vacuum tube

noun
  • A type of electron tube that controls electron current through vacuum between electrodes within a sealed container, usually of glass or metal and often designed to be easily installed in and removed from the equipment in which it is used. 

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