cyst   (sĭst)    n.   Pathology An abnormal membranous sac containing a gaseous, liquid, or semisolid substance. Anatomy A sac or vesicle in the body. Biology A small capsulelike sac that encloses certain organisms in their dormant or larval stage. Botany A thick-walled resting spore, as in certain algae or fungi. [New Latin cystis, from Greek kustis, bladder; see kwes- in Indo-European roots.]

Cyst

Cyst\ (s[i^]st), n. [Gr. ky`stis bladder, bag, pouch, fr. ky`ein to be pregnant. Cf. Cyme.]

1. (Med.) (a) A pouch or sac without opening, usually membranous and containing morbid matter, which is accidentally developed in one of the natural cavities or in the substance of an organ. (b) In old authors, the urinary bladder, or the gall bladder. [Written also cystis.]

2. (Bot.) One of the bladders or air vessels of certain alg[ae], as of the great kelp of the Pacific, and common rockweeds (Fuci) of our shores. --D. C. Eaton.

3. (Zo["o]l.) (a) A small capsule or sac of the kind in which many immature entozoans exist in the tissues of living animals; also, a similar form in Rotifera, etc. (b) A form assumed by Protozoa in which they become saclike and quiescent. It generally precedes the production of germs. See Encystment.

cyst [(sist)]

An abnormal saclike structure that develops in the body and is filled with fluid or semisolid material.

cyst 

Main Entry: cyst
Pronunciation: 'sist
Function: noun
1 : a closed sac having a distinct membrane and developing abnormally in a body cavity orstructure
2 : a body resembling a cyst: as a : a capsule formed about a minute organism going into a resting or spore stage; also : this capsulewith its contents b : a resistant cover about a parasite produced by the parasite or the host —compare HYDATID2a

cyst (sĭst)
n.

1. An abnormal membranous sac containing a gaseous, liquid, or semisolid substance.
2. A sac or vesicle in the body.
3. A small capsulelike sac that encloses certain organisms in their dormant or larval stage.

cyst   (sĭst)  Pronunciation Key  An abnormal membranous sac in the body, containing a gaseous, liquid, or semisolid substance. A small, capsulelike form of certain organisms that develops in response to adverse or extreme conditions. Under adverse conditions, for instance, dinoflagellates form nonmotile resting cysts that fall to the ocean or lake bottom and can remain there for years before reviving. Certain invertebrates, such as the water bear (phylum Tardigrada), also develop cysts.