Main Entry: spo·ro·cyst Pronunciation: -"sist Function: noun 1: a case or cyst secreted by some sporozoans preliminary to sporogony;also: a sporozoan encysted in such a case 2: a saccular body that is the first asexual reproductive form of a digenetic trematode, develops from a miracidium, andbuds off cells from its inner surface which develop into rediae