cross-member vs fanlight

cross-member

noun
  • A beam lying crosswise; a rail. 

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 

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