agnate vs biological father

agnate

noun
  • Any paternal male relative. 

  • A relative whose relation is traced only through male members of the family. 

  • A statement having a similar meaning to another, but a different structure. 

adj
  • allied; akin 

  • Related to someone by male connections or on the paternal side of the family. 

  • Having a similar semantic meaning. 

biological father

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

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