Cf. Theol.: IV. xx., where S. Gregory says “Perhaps this Relation might be compared to that between the Definition and the thing defined.” Nicetas remarks that, just as the definition declares the nature of the defined, so the Personal Word shows forth the Nature of the Father. Suidas (in voce ὃρος) says that the phrase is used to show the Unity of Nature between the Father and the Son. It is not, however, of frequent occurrence.