Etymology
From earlier necessitat, from Medieval Latin necessitātus, perfect past participle of necessitō (“to make necessary”) (see -ate (verb-forming suffix, of participial origin)), from Classical Latin necessitās (“necessity, need”) + -ō. Necessitās is derived from necesse (“unavoidable”) (from ne- (“not”) + cessus (“conceded, given up, yielded”). By surface analysis, necessitō + -ate.