ὄμφαξ

Etymology
It could derive from, but the semantic explanation as a navel-like knob is hardly convincing. Furnée connects and. The variation, as well as the suffix -αξ, would point to origin.

Noun

 * 1) unripe grape, also of olives
 * 2) young girl, not yet ripe for marriage
 * 3) unripe hard breast of a young girl
 * 4) kind of gem, used for seals