The belly button, also known as the navel, is a small, central scar on the abdomen. It is the remnant of the umbilical cord, which connects a developing fetus to its mother during pregnancy. After birth, the umbilical cord is cut, leaving behind the belly button. Belly buttons can vary in shape and size, and they can be classified as either innies or outies. An innie is a belly button that is recessed into the abdomen, while an outie protrudes outward. The belly button has no significant function in adults, but it serves as a reminder of the connection between mother and child.