1. Pertaining or related to a tetrahedron, or to the system of hemihedral forms to which the tetrahedron belongs 
2. Having, or composed of, four sides 
3. Having the form of the regular tetrahedron

Encyclopedia: Tetrahedral

• opened
• opener
• openhanded
• openhandedness
• openhearted
• opening
• opening line
• opening move
• opening night
• openly
• openmouthed
• openness
• openside plane
• openwork
• opepe
• opera
• opera buffa
• opera cloak
• opera comique
• opera company
• opera glasses
• opera hat
• opera hood
• opera house
• opera star