geode /jēˈōd/

1. A rock cavity lined with crystals that have grown inwards, a druse (geology)
2. A rock or stone having this (geology)
3. A rounded hollow nodule of ironstone (mining)

• head-boom
• head-booms
• headborough
• headboroughs
• head boy
• head boys
• head-bummer
• head-butt
• head-butted
• head-butting
• head-butts
• headcase
• headcases
• head-centre
• headchair
• headchairs
• headcheese
• headcheeses
• headcloth
• headcloths
• head cold
• head colds
• head count
• head counts
• head-crash