Source : Webster's Revised Unabridged Dictionary (1913)

Chalazion \Cha*la"zi*on\, n. [NL., fr. Gr. ? dim. of ? hail,
   pimple.] (Med.)
   A small circumscribed tumor of the eyelid caused by retention
   of secretion, and by inflammation of the Melbomian glands.

Source : WordNet®

chalazion
     n : a small sebaceous cyst of the eyelid resulting when a
         Meibomian gland is blocked [syn: {Meibomian cyst}]