Forma is the concept used by Aristotle -- and later, Plato -- to refer to the essence of a thing. The term references all that defines, identifies and differentiates a certain reality: what makes it be what it really is. Aristotle also argues, in direct contradiction to his predecessor, that the form is what guides and provides an outline for the development process. Then, the essence of this form shall become matter. In this sense, it is said that the form exists first in potency, and then in act. Therefore, to create form is to conceive an essence in potency, and, at the same time, to define the guidelines that will enable that potency to finally come into being.