Pronunciation: (sist),[key] —n. 1. Pathol.a closed, bladderlike sac formed in animal tissues, containing fluid or semifluid matter.
2. a bladder, sac, or vesicle.
3. Bot.,Mycol. a. a sporelike cell with a resistant, protective wall.
b. a cell or cavity enclosing reproductive bodies.
4. Zool. a. a sac, usually spherical, surrounding an animal that has passed into a dormant condition.
b. such a sac plus the contained animal.
c. a capsule or resistant covering.
var. of cysto-, before a vowel: cystectomy.
var. of cysto-, as final element in a compound word: statocyst.