An ovum, also known as an egg cell, is the female reproductive cell in many organisms, including humans. It is one of the largest cells in the body and plays a crucial role in reproduction. When fertilized by a sperm cell, the ovum can develop into an embryo, leading to the formation of a new organism. In humans, each ovum is produced in the ovaries and is released during the menstrual cycle in a process called ovulation. The ovum contains genetic material and nutrients necessary for early development. If not fertilized, it will eventually disintegrate and be expelled from the body.