specialty vs string to one's bow

specialty

noun
  • That in which one specializes; a chosen expertise or talent. 

  • A particular or peculiar case. 

  • An attribute or quality peculiar to a species. 

  • A contract or obligation under seal; a contract by deed; a writing, under seal, given as security for a debt particularly specified. 

  • A product that originates in and is characteristic of a place. 

string to one's bow

noun
  • A skill, ability or resource. 

  • A lover, paramour or suitor. 

How often have the words specialty and string to one's bow occurred in a corpus of books? (source: Google Ngram Viewer )