rolly polly vs slater

rolly polly

noun
  • A forward roll or a backwards roll. 

  • A woodlouse. 

slater

noun
  • One who lays slates, or whose occupation is to slate buildings. 

  • Any terrestrial isopod crustacean of the genus Porcellio and allied genera; a woodlouse. 

  • A harsh critic; one who slates or denigrates something. 

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