(n)either of two thickened triangular layers of conjunctiva extending from the nasal edge of the eye to the cornea; it arises from irritation of the pinguecula
The Collaborative International Dictionary of English (GCIDE) v.0.53Collaborative International Dictionary (GCIDE)
‖n.; pl. E. Pterygiums L. Pterygia [ NL., fr. Gr. &unr_;, properly a dim, akin to &unr_; a feather. ] (Med.) A superficial growth of vascular tissue radiating in a fanlike manner from the cornea over the surface of the eye. [ 1913 Webster ]