necessity vs preference

necessity

noun
  • The quality or state of being necessary, unavoidable, or absolutely requisite. 

  • Something which makes an act or an event unavoidable; an irresistible force; overruling power. 

  • Greater utilitarian good; used in justification of a criminal act. 

  • Indispensable requirements (of life). 

  • The negation of freedom in voluntary action; the subjection of all phenomena, whether material or spiritual, to inevitable causation; necessitarianism. 

  • The condition of being needy; desperate need; lack. 

  • Something necessary; a requisite; something indispensable. 

preference

noun
  • The state of being preferred over others. 

  • The option to so select, and the one selected. 

  • The selection of one thing or person over others (with the main adposition being "for" in relation to the thing or person, but possibly also "of") 

  • Preferans, a card game, principally played in Eastern Europe. 

  • A strong liking or personal valuation. 

  • A preferential bias; partiality; discrimination. 

verb
  • To give preferential treatment to; to give a preference to. 

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