dish washer vs dishwasher

dish washer

dishwasher

noun
  • A European bird, the wagtail. 

  • A machine for washing dishes. 

  • Someone who washes dishes, especially one hired to wash dishes in a restaurant. 

  • A bird, the restless flycatcher (Myiagra inquieta). 

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