Priestley in 1946 minted a nice trope with this sign of stomach-tightened nervousness: ''with your bellybutton knockin' against your backbone. '' (It's two words in Merriam-Webster, one word in Webster's New World. ... Button and buttonhole were frequent choices, and a fair sampling called it a belly-hole.

Is belly button a compound word?

Kneecap, eyeball, eyelid, backbone, bellybutton. Two words make it descriptive like knee cap - a cap on your knee or eye ball - a ball in your eye but we don't separate those as two words and bellybutton is no different.

Is it belly button or belly button?

The navel (clinically known as the umbilicus, commonly known as the belly button) is a protruding, flat, or hollowed area on the abdomen at the attachment site of the umbilical cord. All placental mammals have a navel.