thun·der·head 
(thŭndər-hĕd′)
(thŭndər-hĕd′)n.
The swollen upper portion of a thundercloud, usually associated with the development of a thunderstorm.
- freeware
- freeway
- free weight
- freewheel
- freewheeling
- free will
- freewill
- free world
- freewrite
- freewriting
- freezable
- freeze
- freeze blood
- freeze-dry
- freeze-etch
- freeze-etching
- freeze-frame
- freeze frame
- freeze out
- freezer
- freezer burn
- freeze (someone's) blood
- freeze someone's blood
- freezing point
- free zone