Appendicitis
A belly button ring is a body piercing placed in a cauterized area of the belly button.
belly button
umbilical area
A belly piercing is a piercing on the belly button. Where your belly button might go in or out, it is the slight arch you get just above it. it is a piercing through that area. depending on how your belly button is formed. Search google for images.
Umbilical Knot 'Navel' is more common The "Navel" is the area around the "belly button"
Abdomen
You may be pregnant. I would go to a dr
The navel.
The navel.
Umbilical Hernia. Not particularly dangerous, but get it checked out. You'll experience soreness and tenderness around the belly button area, and it's possible your belly button might swell and protrude a little. Usually results from injury or impact to the area.
Umbilical knot
Intestines and uterus if you are a woman.