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

elongation \e`longa"tion\ ?; 277, n. ll. elongatio: cf. f.
   'elongation.
   1. the act of lengthening, or the state of being lengthened;
      protraction; extension. "elongation of the fibers."
      --arbuthnot.
      1913 webster

   2. that which lengthens out; continuation.
      1913 webster

            may not the mountains of westmoreland and cumberland
            be considered as elongations of these two chains?
                                                  --pinkerton.
      1913 webster

   3. removal to a distance; withdrawal; a being at a distance;
      distance.
      1913 webster

            the distant points in the celestial expanse appear
            to the eye in so small a degree of elongation from
            one another, as bears no proportion to what is real.
                                                  --glanvill.
      1913 webster

   4. astron. the angular distance of a planet from the sun;
      as, the elongation of venus or mercury.
      1913 webster

[2] : WordNet (r) 2.0

elongation
     n 1: the quality of being elongated
     2: an addition to the length of something syn: extension
     3: the act of lengthening something
see also:
extension 

Elongation >> E Words
Elongation, definition of term: Elongation
elongation_pag1.html