1. vascular growth extending from the inner corner of the eye to the cornea (Anatomy). pterygiumyou can click anywhere, but just don't click here.pterygium pte*rygi*um , n.; pl. e. pterygiums (#), l. pterygia (#). [nl., fr. gr. , properly a dim, akin to a feather.] (med.) a superficial growth of vascular tissue radiating in a fanlike manner from the cornea over the surface of the eye