Egg sac: The "egg sac" or ovary is one of a pair of reproductive glands in women. They are located in the pelvis, one on each side of the uterus. Each ovary is about the size and shape of an almond. The ovaries have two functions: production of eggs (ova) and female hormones.
Each month, during the menstrual cycle, an egg is released from one ovary. The egg travels from the ovary through a fallopian tube to the uterus.
The ovaries are the main source of female hormones (estrogen and progesterone). These hormones control the development of female body characteristics, such as the breasts, body shape, and body hair. They also regulate the menstrual cycle and pregnancy.