The term 'belly-button' is a colloquial term for the NAVEL, which is the small depression in the center of the abdomen. The medical term for the NAVEL is UMBILICUS, which has nine letters. Outie and innie are two other terms used to describe the shape of the NAVEL. Outie is a protruding NAVEL, while innie is an indented NAVEL. Innies is the plural form of innie. The term 'EDEN' is also sometimes used to refer to the NAVEL, as it is thought to be the place where the umbilical cord was attached.