dormer vs skylight

dormer

noun
  • A room-like, roofed projection from a sloping roof. 

  • A resident of a dormitory. 

skylight

noun
  • A window, dome, or opening in the roof or ceiling, to admit natural light. 

  • Diffuse sky radiation—solar radiation reaching the earth's surface after having been scattered from the direct solar beam by molecules or suspensoids in the atmosphere. 

  • A hole in the upper part of a lava tube, yielding a view of the lava within. 

  • A region of flat, thin ice allowing a submarine to surface. 

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