An ovum, commonly 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 male sperm cell, the ovum can develop into an embryo, leading to the formation of a new organism. In humans, the ovum is produced in the ovaries and is released during the menstrual cycle in a process called ovulation. Each ovum contains half of the genetic material needed for the formation of a new individual, contributing to genetic diversity in species, including humans and animals.