noun a bladderlike vessel; a membranous cavity; a cyst; a cell.
2. vesicle ·noun a small convex hollow prominence on the surface of a shell or a coral.
3. vesicle ·noun a cavity or sac, especially one filled with fluid; as, the umbilical vesicle.
4. vesicle ·noun a small bladderlike body in the substance of vegetable, or upon the surface of a leaf.
5. vesicle ·noun a small, and more or less circular, elevation of the cuticle, containing a clear watery fluid.
6. vesicle ·noun 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.