vesicle

n. [ L. vesicula, dim. of vesica a bladder, blister; akin to Skr. vasti bladder: cf. F. vésicule. ] A bladderlike vessel; a membranous cavity; a cyst; a cell. Specifically: -- [ 1913 Webster ]

(a) (Bot.) A small bladderlike body in the substance of a vegetable, or upon the surface of a leaf. [ 1913 Webster ]

(b) (Med.) A small, and more or less circular, elevation of the cuticle, containing a clear watery fluid. [ 1913 Webster ]

(c) (Anat.) A cavity or sac, especially one filled with fluid; as, the umbilical vesicle. [ 1913 Webster ]

(d) (Zool.) A small convex hollow prominence on the surface of a shell or a coral. [ 1913 Webster ]

(e) (Geol.) A small cavity, nearly spherical in form, and usually of the size of a pea or smaller, such as are common in some volcanic rocks. They are produced by the liberation of watery vapor in the molten mass. [ 1913 Webster ]