egress vs porthole

egress

noun
  • The process of exiting or leaving. 

  • The end of the transit of a celestial body through the disk of an apparently larger one. 

  • An exit or way out. 

verb
  • To exit or leave; to go or come out. 

porthole

noun
  • A circular window set in the hull of a ship. 

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