cairn vs paver

cairn

noun
  • A pile of stones heaped up as a landmark, to guide travelers on land or at sea, or to arrest attention, as in surveying, or in leaving traces of an exploring party, etc. 

  • A cairn terrier. 

  • A rounded or conical heap of stones erected by early inhabitants of the British Isles, apparently as a sepulchral monument. 

paver

noun
  • A flat stone used to pave a pathway, such as a walkway to one's home. 

  • One who paves; one who lays pavement. 

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