incandescence vs top light

incandescence

noun
  • the light so emitted 

  • the emission of visible light by a hot body 

  • great emotion, especially anger 

top light

noun
  • Light from above; toplighting. 

  • Any glazing above a main window, partition or door 

  • A skylight. 

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

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