fanlight vs top light

fanlight

noun
  • a semicircular or semioval window over a door or other window, normally having a fan-like structure of ribs; sometimes hinged to the transom 

  • an electric fan, usually a ceiling fan, that is also a light fixture 

top light

noun
  • The upper (and usually smaller) part (casement) of a window, often hinged a the top 

  • Any glazing above a main window, partition or door 

  • A skylight. 

  • Light from above; toplighting. 

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