octangle
noun/ˈɑk.tæŋ.ɡ(ə)l/
Etymology From oct- + angle.
1
A geometric figure with eight corners, an octagon.
- The angles of any two of the tetrahedra ABCD, A′B′C′D′, and OO′O″O‴ form the angles of a complete syngrammatic octangle whose syngrammatic points are the angles of the other tetrahedron […]1853 May, Thomas Weddle, “On certain geometrical relations between a surface of the second degree and a tetrahedron whose edges touch the surface”, in The Cambridge and Dublin Mathematical Journal, volume 8, page 130: