- necessary ► ADJECTIVE 1) required to be done, achieved, or present; needed. 2) that must be; inevitable: a necessary result.► NOUN 1) (necessaries) the basic requirements of life, such as food and warmth. 2) (the necessary) informal the action, item, or money required.ORIGIN Latin necessarius, from necesse 'be needful' .
English terms dictionary. 2015.