The Collaborative International Dictionary of English v.0.48:

Vanishing \Van"ish*ing\,
   a. & n. from Vanish, v.
   [1913 Webster]

   Vanishing fraction (Math.), a fraction which reduces to the
      form 0/0 for a particular value of the variable which
      enters it, usually in consequence of the existence of a
      common factor in both terms of the fraction, which factor
      becomes 0 for this particular value of the variable.
      --Math. Dict.

   Vanishing line (Persp.), the intersection of the parallel
      of any original plane and the picture; one of the lines
      converging to the vanishing point.

   Vanishing point (Persp.), the point to which all parallel
      lines in the same plane tend in the representation.
      --Gwilt.

   Vanishing stress (Phon.), stress of voice upon the closing
      portion of a syllable. --Rush.
      [1913 Webster]

WordNet (r) 3.0 (2006):

vanishing point
    n 1: the point beyond which something disappears or ceases to
         exist
    2: the appearance of a point on the horizon at which parallel
       lines converge