Munro vs tor

Munro

noun
  • Any Scottish mountain having a height of more than 3,000 feet; named after Sir Hugh Thomas Munro, Scottish mountaineer 

name
  • A Scottish surname from Scottish Gaelic, variant of Monroe. 

tor

noun
  • A hill with such rock formation. 

  • A craggy outcrop of rock on the summit of a hill, created by the erosion and weathering of rock. 

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