outlying area vs outpost

outlying area

outpost

noun
  • A military post stationed at a distance from the main body of troops. 

  • An outlying settlement. 

  • The body of troops manning such a post. 

  • A square protected by a pawn that is in or near the enemy's stronghold. 

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