#essential__necessity__requirement__requisite__necessary  anything indispensable; "food and shelter are necessities of life"; "the essentials of the good life"; "allow farmers to buy their requirements under favorable conditions"; "a place where the requisites of water fuel and fodder can be obtained"
  exclusion:  inessential
  supertype:  entity_playing_some_role (pm)  e.g., an agent, an owner
  subtype:  desideratum  something desired as a necessity; "the desiderata for a vacation are time and money"
  subtype:  want__need  anything that is necessary but lacking; "he had sufficient means to meet his simple needs"; "I tried to supply his wants"

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