AR vs augmented reality

AR

noun
  • alternate reality 

  • an assault rifle or automatic rifle. 

  • area record: best achievement among those by persons from a given continent 

  • an AR-15 personal semi-automatic rifle, M-16 assault rifle, M-4 carbine, derivative or related gun; the Armalite AR family and derivatives. 

name
  • Postal abbreviation of Arkansas 

augmented reality

noun
  • The merging of a view of the real-world environment upon a digital image in real time. 

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