lieberkuhn

from The Collaborative International Dictionary of English v.0.48
Lieberkuhn \Lie"ber*k["u]hn\ (l[=e]"b[~e]r*k[.u]n), prop. n.
   [Named after a German physician and instrument maker, J. N.
   Lieberk["u]hn.] (Optics)
   A concave metallic mirror attached to the object-glass end of
   a microscope, to throw down light on opaque objects; a
   reflector.
   [1913 Webster]
    

[email protected]