indicatrix

== English == === Etymology === Learned borrowing from Latin indicātrīx. By surface analysis, indicate +‎ -trix. === Noun === indicatrix (plural indicatrices) (mathematics, crystallography) An ellipsoid whose three axes represent the refractive indices of an anisotropic crystal for light following different directions with respect to the crystal axes ==== Derived terms ==== Tissot's indicatrix === References === “indicatrix, n.”, in OED Online ⁠, Oxford: Oxford University Press, launched 2000.