oniscid vs slater

oniscid

noun
  • Any of the Oniscidae; a woodlouse. 

slater

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

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

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

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