We study the anisotropic optical properties of a superconducting single crystal of Nd{sub 2-x}CeâCuO{sub 4-δ} (xâ0.16). The two components of the dielectric tensor and its orientation with respect to the sample surface are obtained by analysis of ellipsometric data measured at room temperature from 1.4 to 5.1 eV. The optical anisotropy originates in the different spectral behavior of these two components. The ordinary dielectric function, which is related to the copper-oxygen planes, exhibits metallic character. The extraordinary component, related to excitations along the c axis, is nonmetallic and rather featureless. {copyright} {ital 1997} {ital The American Physical Society}