It is a reproductive Cell produced by a woman.

Human ova are extremely minute, measuring about 0.2 mm. in diameter, and are enclosed within the egg follicles of the ovaries; as a rule each follicle contains a single ovum, but sometimes two or more are present. By the enlargement and subsequent rupture of a follicle at the surface of the ovary, an ovum is liberated and conveyed by the uterine tube to the cavity of the Uterus. Unless it be fertilized it undergoes no further development and is discharged from the Uterus, but if Fertilization take place it is retained within the Uterus and is developed into a new being. In appearance and structure the ovum differs little from an ordinary Cell, but distinctive names have been applied to its several parts; thus, the Cell substance is known as the yolk or oöplasm, the nucleus as the germinal vesicle, and the nucleolus as the germinal spot. The ovum is enclosed within a thick, transparent envelope, the zona striata or zona pellucida, adhering to the outer surface of which are several layers of cells, derived from those of the follicle and collectively constituting the corona radiata.

When an ovum is fully mature, the ovarian follicle ruptures and the ovum is released. This process, known as ovulation, always occurs 14 days prior to the next predicted menses, or menstrual flow. Once released, the ovum is capable of being fertilized for approximately 36 hours. Sperm deposited in the vagina near the time of ovulation, may move through the cervix and Uterus to the Fallopian tubes. Embryonic development begins with Fertilization, in which the male germ Cell, the sperm, fuses with the female germ Cell, the ovum, to form a zygote. Based on the dating of pregnancy from the first day of the last menstrual period, pregnancy lasts approximately 280 days (10 lunar months or 9 calendar months). However, the actual duration of prenatal development is about two weeks less.

Here is an incredible fact about the largest and smallest cells of the human body: Both are the “bookends” for creating life. The smallest Cell is the male sperm Cell—spermatozoa. At the other end of the scale is the female egg Cell—the ovum. All cells, and therefore all life, fall between these cells in size. But to create life, the largest and the smallest cells combine. It is interesting that the two most important cells of all are the largest and smallest, with all the rest falling in between. If two ova are fertilized at the same time, the mother will have twins.