snail vs univalve

snail

noun
  • The pod of the snail clover. 

  • 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. 

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

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

verb
  • To move or travel very slowly. 

univalve

noun
  • A univalve mollusk or its shell. 

adj
  • having one valve; typically used to refer to mollusks, notably slugs and snails. 

  • consisting of a single valve or piece, used to refer to a shell. 

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