biological father vs dad

biological father

noun
  • The man from whom one inherits half of one's DNA and from whom men inherit their Y chromosome. 

dad

noun
  • A father, a male parent. 

  • A lump or piece. 

  • A blow; act of striking something. 

  • Used to address an older adult male 

  • Used to address one's father 

verb
  • To throw against something; to dash. 

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