characteristic vs essential

characteristic

adj
  • Being a distinguishing feature of a person or thing. 

noun
  • A distinguishing feature of a person or thing. 

  • For a given field or ring, a natural number that is either the smallest positive number n such that n instances of the multiplicative identity (1) summed together yield the additive identity (0) or, if no such number exists, the number 0. 

  • The integer part of a logarithm. 

  • The distinguishing features of a navigational light on a lighthouse etc by which it can be identified (colour, pattern of flashes etc.). 

essential

adj
  • Being in the basic form; showing its essence. 

  • Necessary. 

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

  • 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. 

noun
  • A necessary ingredient. 

  • A fundamental ingredient. 

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