necessity
1. [ noun ] the condition of being essential or indispensable
Related terms: need urgency requisiteness necessitate necessary unnecessary
2. [ noun ] anything indispensable
Synonyms: requirement essential necessary requisite
Examples:

"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"

Related terms: inessential entity thing need must desideratum want
Similar spelling:   necessitous
  necessitate