1. (n.) A simple podlike pericarp which contains several seeds and opens along the inner or ventral suture, as in the peony, larkspur and milkweed.

2. (n.) A small cavity, tubular depression, or sac; as, a hair follicle.

3. (n.) A simple gland or glandular cavity; a crypt.

4. (n.) A small mass of adenoid tissue; as, a lymphatic follicle.

alveolation alveolus antrum armpit basin boll bowl burr capsule cavity cod concave concavity crater crypt cup depression dip fold funnel chest hole hollow hollow shell hull husk lacuna legume legumen pease cod pericarp pit pocket pod punch bowl scoop seed pod seed vessel seedbox seedcase shell silique sink sinus socket trough vug