metastrophe

Century Dictionary and Cyclopedia

1. n. Change or interchange; specifically, in crystallog. See the extract. A solid figure is symmetrical to an axis when every radius vector moving in a plane perpendicular to the axis and meeting a point of the figure would also meet corresponding points at the same distances from the axis at each revolution through an arc-angle of . The aspect of such a solid figure will not therefore be changed by a revolution of the solid round this axis through the angle , and any portion of its surface so revolving will move into a position in which it will be congruent with another portion of the surface entirely corresponding to it.