massif vs mons

massif

noun
  • A principal mountain mass. 

  • A block of the earth's crust bounded by faults or flexures and displaced as a unit without internal change; normally consists of gneisses and schists 

mons

noun
  • A mountain or extinct volcano on a planet or a moon. 

  • The pubic mound or mons pubis. In human anatomy or in mammals in general, the mons pubis (Latin for "pubic mound"), also known as the mons veneris (Latin, mound of Venus) or simply the mons, is the adipose tissue lying above the pubic bone of adult females, anterior to the pubic symphysis. The mons pubis forms the anterior portion of the vulva. 

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