Chalazion

Source: all about vision
A chalazion is a benign, painless bump or nodule inside the upper or lower eyelid.
Chalazia (plural for chalazion) result from healed internal styes that no longer are infectious. These cyst-like nodules form around an oil gland (meibomian) within the eyelid, resulting in red, swollen eyelids.
The contents of a chalazion include pus and blocked fatty secretions (lipids) that normally help lubricate the eye but can no longer drain out.


See more
http://www.allaboutvision.com/conditions/chalazion.htm