blood brother vs bub

blood brother

noun
  • A brother by blood: a brother-german or half-brother, as distinguished from step-brothers. 

  • An unrelated male considered to share such a strong relationship generally. 

  • An unrelated male considered to share a brother-like relationship established by a ceremonial sharing of blood in some cultures. 

bub

noun
  • A young brother; a little boy; a familiar term of address for a small boy. 

  • A term of familiar address; bubba; bubby. 

  • A woman's breast. 

  • A baby. 

  • An alcoholic malt liquor, especially beer. 

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