Mother vs mater

Mother

name
  • A title given to a nun or a priestess. 

  • One of the triune goddesses of the Lady in Wicca alongside the Crone and Maiden and representing a woman older than a girlish Maiden but younger than an aged Crone. 

  • A title given to the personification of a force of nature or abstract concept, such as Mother Nature, Mother Russia, or Mother Earth. 

mater

noun
  • A meninx; the dura mater, arachnoid mater, or pia mater of the brain. 

  • Mother. 

  • Someone or something that mates. 

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