APA Dictionary of Psychology

a small pouchlike cavity in an ovary in which an ovum develops (see oogenesis). At ovulation, one of the follicles ruptures and releases a mature ovum into a fallopian tube, where it may be fertilized. The ruptured follicle becomes the site of the corpus luteum. Also called ovarian follicle. [Reijner de Graaf (1641–1673), Dutch histologist]