gastropod vs snail

gastropod

noun
  • Any member of a class of mollusks (Gastropoda) that includes snails and slugs; univalve mollusk. 

snail

noun
  • Any of very many animals (either hermaphroditic or nonhermaphroditic), of the class Gastropoda, having a coiled shell. 

  • A spiral cam, or a flat piece of metal of spirally curved outline, used for giving motion to, or changing the position of, another part, as the hammer tail of a striking clock. 

  • A tortoise or testudo; a movable roof or shed to protect besiegers. 

  • A slow person; a sluggard. 

  • A locomotive with a prime mover but no traction motors, used to provide extra electrical power to another locomotive. 

  • The pod of the snail clover. 

verb
  • To move or travel very slowly. 

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