noun: (Aristotelian metaphysics) The complete realisation and final form of some potential concept or function; the conditions under which a potential thing becomes actualized.
noun: (specifically) In the metaphysics of Aristotle (384–322 BCE) and Gottfried Wilhelm Leibniz (1646–1716): a soul; a monad (Leibniz).
noun: (chiefly philosophy) A particular type of motivation, need for self-determination, and inner strength directing life and growth to become all one is capable of being; the need to actualize one's beliefs; having both a personal vision and the ability to actualize that vision from within.