dihedron
/daɪˈhiːdrən/
noun
- A geometric shape formed by two flat surfaces (faces) meeting at a straight line (edge), like an open book or a folded piece of paper.
- In geometry class, we learned that a dihedron has two faces and one edge.
- A simple dihedron can be made by bending a sheet of metal along a straight line.
- The teacher showed the class a dihedron by folding a piece of cardboard in half.