merohedral, a. Cryst.
(mɛrəʊˈhiːdrəl)
[f. mero-1 + Gr. ἕδρα seat, base + -al1.]
Of a crystal: Having less than the full number of faces admitted by the type of symmetry to which it belongs. So meroˈhedric a. in the same sense (Webster Suppl. 1902); meroˈhedrism, the property of being merohedral.
| 1888 Teall Brit. Petrogr. 438 Merohedrism, a crystallographic term embracing both hemihedrism and tetartohedrism. 1895 Story-Maskelyne Crystallogr. §137 The term merohedral will be reserved for certain cases in which a defalcation is met with in the faces of a crystal out of accord with any fixed law of symmetry; though sometimes such a merohedral crystal simulates the mode of grouping of a crystal belonging to a different type of symmetry from its own. 1899 W. J. Lewis Crystallogr. 149 The forms of certain classes were regarded as merohedral divisions of a more symmetrical form. Ibid. 259 The views underlying the ideas of merohedrism lead to inconsistencies. |