maternal cousin vs second cousin

maternal cousin

noun
  • A child of one's mother's sibling 

  • A more distant relative of one's mother who is not a direct ancestor 

second cousin

noun
  • A grandchild of a grandparent's sibling. 

  • A relative who has with the other person only two great-grandparents in common, but where the parents and grandparents are different. 

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