roof·tree 
(rftrē′, rf-)
(rftrē′, rf-)n.
The ridgepole of a roof.
- exterminatory
- extern
- external
- external auditory canal
- external capsule
- external-combustion engine
- external ear
- externalism
- externalist
- externality
- externalization
- externalize
- externally
- external phase
- external respiration
- externe
- externship
- exteroceptive
- exteroceptor
- exterritorial
- exterritoriality
- exterritorially
- extinct
- extinction
- extinctive