pentahedral, a.
(pɛntəˈhiːdrəl, -ˈhɛdrəl)
Also pentaedral.
[f. penta- + Gr. ἕδρα seat, base + -al1: cf. hexahedral.]
Of a solid figure or body: Having five faces; esp. having five lateral faces, five-sided (as a prism of pentagonal section). So † pentaˈhedrical, pentaˈhedrous adjs. in same sense; pentaˈhedron, a solid figure having five faces.
| 1804 Watt in Phil. Trans. XCIV. 310 note, Hexaedral and *pentaedral prisms are most abundant; then the tetraedral, the triedral, heptaedral, and octaedral. 1826 Kirby & Sp. Entomol. IV. 266 Pentaedral, that hath five sides. |
| 1658 Phillips, *Pentahedrical figure,..a figure which hath five sides. 1661 in Blount Glossogr. |
| 1775 Ash, *Pentahedron (a different spelling), the pentaedron. Ibid., Pentaedron, a pillar with five sides. |
| a 1728 Woodward Fossils (1729) I. 120 The *pentaedrous Columnar Coralloid Bodies are compos'd of Plates set lengthways. |