gladius vs spicule

gladius

noun
  • A pen, a hard internal bodypart of certain cephalopods, made of chitin-like material. 

  • A Roman sword roughly two feet long. 

spicule

noun
  • Any of many needle-like crystalline structures that provide skeletal support in marine invertebrates like sponges. 

  • A needle-like mating structure found only in male nematodes. 

  • A sharp, needle-like piece. 

  • A tiny glass flake formed during the manufacture of glass vials 

  • A small spike of flowers. 

  • A jet of matter ejected from the photosphere of the sun. 

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