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

back-formation \back"-forma`tion\ n. linguistics
   1. a word invented usually unwittingly by subtracting an
      affix on the assumption that a familiar word derives from
      it, such as emote from emotion.
      wordnet 1.5 +pjc

   2. the process of inventing a back-formation1.
      pjc

[2] : WordNet (r) 2.0

back-formation
     n : a word invented usually unwittingly by subtracting an
         affix on the assumption that a familiar word derives
         from it

Backformation >> B Words
Backformation, definition of term: Backformation
backformation_pag1.html