foreground vs vanguard

foreground

noun
  • The application the user is currently interacting with; the application window that appears in front of all others. 

  • The elements of an image which lie closest to the picture plane. 

  • The subject of an image, often depicted at the bottom in a two-dimensional work. 

verb
  • To place in the foreground (physically or metaphorically). 

vanguard

noun
  • The person(s) at the forefront of any group or movement. 

  • The leading units at the front of an army or fleet. 

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