n. (pl. -ies) 1 a an indispensible thing; a necessary (central heating is a necessity). b (usu. foll. by of) indispensability (the necessity of a warm overcoat). 2 a state of things or circumstances enforcing a certain course (there was a necessity to hurry). 3 imperative need (necessity is the mother of invention). 4 want; poverty; hardship (stole because of necessity). 5 constraint or compulsion regarded as a natural law governing all human action. of necessity unavoidably.
[ ME f. OF necessité f. L necessitas -tatis f. necesse needful ]