maternal cousin vs paternal cousin

maternal cousin

noun

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

  • A child of one's mother's sibling 

paternal cousin

noun

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

  • A child of one's father's sibling 

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