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

backspace \backspace\, backspacer \backspacer\n.
   1. the key on a typewriter or other keyboard used for back
      spacing.

   syn: backspace key.
        wordnet 1.5

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

backspace \backspace\, v. i.
   in typing text, to press the backspace key so as to
   reposition the carriage or cursor on the previous space.
   pjc

[3] : WordNet (r) 2.0

backspace
     v : hit the backspace key on a computer or typewriter keyboard;
         "to erase, you must backspace"

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Backspace, definition of term: Backspace
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