a. Math. [f. Gr. ἀν not + ἄλλαγμα(τ-) something given in exchange, lit. a change (f. ἀλλάττ-ειν to change) + -IC.] Not changed in form by ‘inversion’: applied to the surfaces of certain solids, as the sphere.
1869. Clifford, Brit. Assoc. Rep., 8. On the Umbilici of Anallagmatic Surfaces.
1874. Salmon, Geom. Three Dimens., § 516. A surface which is its own inverse with regard to any point has been called an anallagmatic surface.
