<p><strong>Noun</strong></p><ul><li>Pathology. a closed, bladderlike sac formed in animal tissues, containing fluid or semifluid matter.</li><li>a bladder, sac, or vesicle.</li><li>Botany, Mycology. a sporelike cell with a resistant, protective wall.</li><li>a cell or cavity enclosing reproductive bodies.</li><li>Zoology. a sac, usually spherical, surrounding an animal that has passed into a dormant condition.</li><li>such a sac plus the contained animal.</li><li>a capsule or resistant covering.</li></ul>