follicle

(fŏlˈĭ-kəl)

1. Anatomy
   a. A small bodily cavity or sac.
   b. A crypt or minute cul-de-sac or lacuna, such as the depression in the skin from which the hair emerges.
   c. An ovarian follicle.
   d. A spherical mass of cells usually containing a cavity.
2. Botany A dry, single-chambered fruit that splits along only one seam to release its seeds, as in larkspur and milkweed.