background vs essential

background

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). 

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. 

essential

adj
  • Having the nature of essence; not physical. 

  • Necessary. 

  • Necessary for survival but not synthesized by the organism, thus needing to be ingested. 

  • Being in the basic form; showing its essence. 

  • Really existing; existent. 

  • Very important; of high importance. 

  • Such that each complementary region is irreducible, the boundary of each complementary region is incompressible by disks and monogons in the complementary region, and no leaf is a sphere or a torus bounding a solid torus in the manifold. 

  • Idiopathic. 

noun
  • A necessary ingredient. 

  • A fundamental ingredient. 

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