1needed to be done, achieved, or present; essential:they granted the necessary planning permission it’s not necessary for you to be here
2determined, existing, or happening by natural laws or predestination; inevitable:a necessary consequence Philosophy (of a concept, statement, etc.) inevitably resulting from the nature of things, so that the contrary is impossible. Philosophy (of an agent) having no independent volition.
the basic requirements of life, such as food and warmth: not merely luxuries, but also the common necessaries poor people complaining for want of the necessaries of life
) informal the action or item needed:see when they need a tactful word of advice and do the necessary
) British informal the money needed: a bag containing my wallet: the money, the necessary