- necessity - the condition of being essential or indispensable
--1 is a kind of need, demand
--1 has particulars: requisiteness; urgencyDerived form: verb necessitate1 - necessity, essential, 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"
--2 is a kind of thing
--2 has particulars: desideratum; must; need, wantDerived form: verb necessitate1