helmet vs sailor

helmet

noun
  • A naked shield or protuberance on the top or fore part of the head of a bird. 

  • The hood-shaped upper sepal or petal of some flowers, as of the monkshood or the snapdragon. 

  • The feature above a shield on a coat of arms. 

  • The glans penis. 

  • A hard, protective head covering, typically part of armour. 

  • A contemptible or stupid person. 

  • The upper part of a chemist's retort. 

verb
  • To cover with, or as if with, a helmet. 

sailor

noun
  • Any of various nymphalid butterflies of the genera Neptis, Pseudoneptis and Phaedyma, having white markings on a dark base and commonly flying by gliding. 

  • A member of the crew of a vessel; a mariner; a common seaman. 

  • A person who sails sailing boats as a sport or recreation. 

  • A person in the business of navigating ships or other vessels 

  • Someone knowledgeable in the practical management of ships. 

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