| 释义 |
dihedron Math.|daɪˈhiːdrən|
[mod. f. Gr. δι-, δισ- twice + ἕδρα seat, base: cf. tetrahedron.]
In the geometrical theory of groups, the portion of two superposed planes bounded by (or contained within) a regular polygon.
According to Klein, the six regular solids are dihedron (dieder), tetrahedron, octahedron, cube or hexahedron, ikosahedron, pentagon-dodecahedron.
[1828Webster, Dihedron, a figure with two sides.] 1888G. G. Morrice tr. F. Klein's Lect. on Ikosahedron 3 We can denote this latter by considering the portion of the plane limited by the sides of the n-gon to be doubled, as a regular solid—a dihedron, as we will say: only that this solid, contrary to the elementary notion of such, encloses no space. |
