grandsire vs oma

grandsire

noun
  • Grandfather. 

  • The sire of a sire, paternal grandfather 

  • Any of a number of methods of change-ringing on bells. 

  • Any male ancestor. 

oma

noun
  • grandmother, grandma. 

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