D defs.my
Entry 2 senses Webster, 1913

Tetrahedral

/tĕtˌ-rəh-ēd'-rəl/ · Tet·ra·he·dral · IPA /tˌɛtrəhˈiːdrəl/
01 a. Having, or composed of, four sides.
  1. 1.
    Having, or composed of, four sides.
  2. 2.
    Having the form of the regular tetrahedron.(Crystallog.)
Phrases & compounds
Tetrahedral angle — a solid angle bounded or inclosed by four plane angles.