background vs extraction

background

noun
  • One's social heritage, or previous life; what one did in the past. 

  • Information relevant to the current situation about past events; history. 

  • The image or color over which a computer's desktop items are shown (e.g. icons or application windows). 

  • A part of the picture that depicts scenery to the rear or behind the main subject; context. 

  • A less important feature of scenery (as opposed to foreground). 

  • A type of activity on a computer that is not normally visible to the user. 

adj
  • Less important or less noticeable in a scene or system. 

verb
  • To put in a position that is not prominent. 

  • To gather and provide background information (on). 

extraction

noun
  • A person's origin or ancestry. 

  • A removal of a tooth from its socket. 

  • Something extracted, an extract, as from a plant or an organ of an animal etc. 

  • An act of extracting or the condition of being extracted. 

  • An act of removing someone from a hostile area to a secure location. 

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