Optics. [Named after the inventor J. N. Lieberkühn (1711–56), an anatomist of Berlin.] A silver concave reflector fixed on the object-glass end of a microscope to bring the light to focus on an opaque object.
1867. J. Hogg, Microsc., I. ii. 58. Illuminated by a combination of the parabola and a fiat Lieberkuhn.
