肚脐

[ noun ]
a scar where the umbilical cord was attached
<noun.body>
you were not supposed to show your navel on televisionthey argued whether or not Adam had a navel
she had a tattoo just above her bellybutton

bellybutton \bel"ly*but`ton\, belly button \bel"ly but`ton\, n.
The depression in the middle of the abdomen in humans left as
a residue of the umbilical cord; the umbilicus; the navel[1].
[PJC]