HEMIHEDRAL a.
Having half of the similar parts of a crystals, instead of all; consisting of half the planes which full symmetry would require, as when a cube has planes only on half of its eight solid angles, or one plane out of a pair on each of its edges; or as in the case of a tetrahedron, which is hemihedral to an octahedron, it…
HOOP n.
een these two, respectively. -- Flat hoop, a wooden hoop dressed flat on both sides. -- Half-round hoop, a wooden hoop left rounding and undressed on the outside. -- Hoop iron, iron in thin narrow strips, used for making hoops. -- Hoop lock, the fastening for uniting the ends of wooden hoops by notching and interlo…