tri·he·dron 
(trī-hēdrən)
(trī-hēdrən)n. pl. tri·he·drons or tri·he·dra (-drə)
A figure formed by three planes meeting at a point. Also called trihedral.
- open-end
- open-ended
- open-endedly
- open-endedness
- open-end investment company
- open-end wrench
- open enrollment
- opener
- open-eyed
- open eyes
- open-faced
- open fire
- openhanded
- openhandedly
- openhandedness
- openhearted
- openheartedly
- openheartedness
- open-hearth
- open-heart surgery
- open house
- opening
- open interval
- open-label
- open letter