In botany, the term capsule may have any of several meanings:
1. A dry, dehiscent fruit, developed from two or more carpels and containing numerous seeds. (Dehiscent means the spontaneous opening of a plant structure at maturity.) The seeds of a dehiscent fruit are released in various ways, for example, by longitudinal splitting from apex to base, the separated parts being known as valves, as in the iris; by the formation of pores near the top of the fruit, as in the snapdragon; or in the pyxidium, by detachment of a lid following equatorial dehiscence as in the scarlet pimpernel.
3. In some kinds of bacteria, a gelatinous envelope surrounding the cell wall.
4. The connective tissue investment of an organ, providing mechanical support.