Cyst, n.

n. [Gr. κύστις, bladder, bag, pouch, from κύειν, to hold, contain, swell.] (Physiol.) A pouch or sac, without opening, and commonly of a membranous nature, which is accidentally developed in one of the natural cavities, or in the substance of organs: it contains morbid matter, differing in color and quality in different cases. [Written also cystis.] Dunglison.