[1] : The Collaborative International Dictionary of English v.0.48

aplanatic \ap`lanat"ic\, a. gr. 'a priv. + ? disposed to
   wander, wandering, ? to wander. opt.
   having two or more parts of different curvatures, so combined
   as to remove spherical aberration; -- said of a lens.
   1913 webster

   aplanatic focus of a lens opt., the point or focus from
      which rays diverging pass the lens without spherical
      aberration. in certain forms of lenses there are two such
      foci; and it is by taking advantage of this fact that the
      best aplanatic object glasses of microscopes are
      constructed.
      1913 webster
see also:
aplanatic focus 

[2] : WordNet (r) 2.0

aplanatic
     adj : free from or corrected for spherical aberration; "an
           aplanatic mirror"

Aplanatic >> A Words
Aplanatic, definition of term: Aplanatic
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