The Collaborative International Dictionary of English v.0.48:
Chemosis \Che*mo"sis\, n. [NL., fr. Gr. ? a swelling of the cornea resembling a cockleshell, fr. ? a gaping, hence a cockleshell.] (Med.) Inflammatory swelling of the conjunctival tissue surrounding the cornea. -- Che*mot"ic, a. [Webster 1913 Suppl.]