chief vs essential

chief

noun
  • The principal part or top of anything. 

  • A leader or head of a group of people, organisation, etc. 

  • An informal term of address. 

  • An informal term of address for a Native American or First Nations man. 

  • The top part of a shield or escutcheon; more specifically, an ordinary consisting of the upper part of the field cut off by a horizontal line, generally occupying the top third. 

verb
  • To smoke cannabis. 

adj
  • Primary; principal. 

  • Intimate, friendly. 

essential

noun
  • A fundamental ingredient. 

  • A necessary ingredient. 

adj
  • 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. 

  • Having the nature of essence; not physical. 

  • 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. 

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