diplopia

from WordNet (r) 3.0 (2006)

diplopia
    n 1: visual impairment in which an object is seen as two
         objects; "diplopia often disappears when one eye is
         covered" [syn: {diplopia}, {double vision}]

from The Collaborative International Dictionary of English v.0.48

Diplopia \Di*plo"pi*a\, Diplopy \Dip"lo*py\, n. [NL. diplopia,
   from Gr. ? double + the root of ? sight: cf. F. diplopie.]
   (Med.)
   The act or state of seeing double.
   [1913 Webster]

   Note: In crossed or heteronymous diplopia the image seen by
         the right eye is upon the left hand, and that seen by
         the left eye is upon the right hand. In homonymous
         diplopia the image seen by the right eye is on the
         right side, that by the left eye on the left side. In
         vertical diplopia one image stands above the other.
         [1913 Webster]