The largest cell in the human body is the female ovum, or egg cell. It measures about 120 micrometers (0.12 mm) in diameter, making it visible to the naked eye without magnification. The ovum is approximately 20 times larger than the male sperm cell and is the reproductive cell in females, containing nutrients to support early embryo development after fertilization

. While neurons (nerve cells) are the longest cells in the human body, the ovum holds the distinction of being the largest by size