jalousie vs louver

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. 

louver

noun
  • Any of a system of slits, as in the hood of an automobile, for ventilation. 

  • A type of turret on the roof of certain medieval buildings designed to allow ventilation or the admission of light. 

  • A series of sloping overlapping slats or boards which admit air and light but exclude rain etc. 

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