[cyst] n [NL cystis, fr. Gk kystis bladder, pouch; akin to Skt svasiti he blows, snorts--more at wheeze] (ca. 1720) 1: a closed sac having a distinct membrane and developing abnormally in a cavity or structure of the body
2: a body resembling a cyst: as a: a resting spore of many algae b: a gas-filled vesicle (as of a rockweed or bladderwort) c: a capsule formed about a minute organism going into a resting or spore stage; also: this capsule with its contents d: a resistant cover about a parasite produced by the parasite or the host