The definition of necessary is being essential or required.
(adjective)An example of necessary is a high school diploma or GED to obtain college admittance.
See necessary in Webster's New World College Dictionary
adjective
Origin: ME < L necessarius < necesse, unavoidable, necessary < ne-, not + cedere, to give way: see cede
noun pl. necessaries
See necessary in American Heritage Dictionary 4
adjective
Origin:
Origin: Middle English necessarie
Origin: , from Old French necessaire
Origin: , from Latin necessārius
Origin: , from necesse; see ked- in Indo-European roots
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