Source : WordNet®

typographical error
     n : a mistake in printed matter resulting from mechanical
         failures of some kind [syn: {misprint}, {erratum}, {typo},
          {literal error}, {literal}]

Source : Free On-Line Dictionary of Computing

typographical error
     
        (typo) An error while inputting text via keyboard, made
        despite the fact that the user knows exactly what to type in.
        This usually results from the operator's inexperience at
        keyboarding, rushing, not paying attention, or carelessness.
     
        Compare: {mouso}, {thinko}.
     
        (1996-04-20)