pte·ryg·i·um 
(tə-rĭjē-əm)
(tə-rĭjē-əm)n. pl. pte·ryg·i·ums or pte·ryg·i·a (-ē-ə)
An abnormal mass of tissue arising from the conjunctiva of the inner corner of the eye that obstructs vision by growing over the cornea.
[New Latin, from Greek pterugion, diminutive of pterux, pterug-, wing; see PTERYGOID.]
pte·rygi·al (-əl) adj.