hull vs perigone

hull

noun
  • The outer covering of a fruit or seed. 

  • Any covering. 

  • The body or frame of a vessel, such as a ship or plane. 

  • The smallest set that possesses a particular property (such as convexity) and contains every point of A; slightly more formally, the intersection of all sets which possess the specified property and of which A is a subset. 

verb
  • To hit (a ship) in the hull with cannon fire etc. 

  • To remove the outer covering of a fruit or seed. 

perigone

noun
  • In mosses, the involucral bracts of a male flower. 

  • perianth 

  • A sac surrounding the generative bodies in the gonophore of a hydroid. 

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