Vesicle

Part of speech: noun (n.)

1. A bladderlike vessel; a membranous cavity; a cyst; a cell. Specifically: --(a) (Bot.)

2. A small bladderlike body in the substance of vegetable, or upon the surface of a leaf. (b) (Med.)

3. A small, and more or less circular, elevation of the cuticle, containing a clear watery fluid.