/duy hee"dreuhl/ , adj.
1. having or formed by two planes.
2. of or pertaining to a dihedron.
n.
3. dihedron.
4. Aeron. the angle at which the right and left wings or the halves of any other horizontal surface of an airplane or the like are inclined upward or downward.
[ 1790-1800; DI- 1 + -HEDRAL ]