A definition of a thing (''definitio rei'') is the maintenance that other ideas are contained in a certain term (assuming common usage) referring to a thing. For example, ''Man is a rational animal''.<ref name=p78>Arnauld, Antoine (1662). ''Logic or the Art of Thinking: Being The Port Royal Logic''. Ed. and trans. T. S. Baynes. London: W. Blackwood, 1850 (''La logique ou l'art de penser; contenant outre les règles communes, plusieurs observations nouvelles, propres à former le jugement'', Paris), pp. 78-9.</ref> | A definition of a thing (''definitio rei'') is the maintenance that other ideas are contained in a certain term (assuming common usage) referring to a thing. For example, ''Man is a rational animal''.<ref name=p78>Arnauld, Antoine (1662). ''Logic or the Art of Thinking: Being The Port Royal Logic''. Ed. and trans. T. S. Baynes. London: W. Blackwood, 1850 (''La logique ou l'art de penser; contenant outre les règles communes, plusieurs observations nouvelles, propres à former le jugement'', Paris), pp. 78-9.</ref> |