brother-in-law vs stepmama

brother-in-law

noun
  • The husband of the sibling of one's spouse. 

  • The brother of the spouse of one's sibling. 

  • The brother of one's spouse. 

  • The husband of one's sibling. 

stepmama

noun
  • stepmother 

How often have the words brother-in-law and stepmama occurred in a corpus of books? (source: Google Ngram Viewer )