contralto vs violist

contralto

noun
  • The lowest female voice or voice part, falling between tenor and mezzo-soprano. The terms contralto and alto refer to a similar musical pitch, but among singers, the term contralto is reserved for female singers; the equivalent male form is counter-tenor. Originally the contratenor altus was a high countermelody sung against the tenor or main melody. 

violist

noun
  • A person who plays the viola. 

  • A person who plays the viol. 

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