explorer vs traveler

explorer

noun
  • One who explores something 

  • A person who by means of travel (notably an expedition) searches out new information. 

  • A visual representation of a file system etc. through which the user can navigate. 

  • Any of various hand tools, with sharp points, used in dentistry. 

traveler

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