The Difference Between a Short Sale and a PreForeclosure

Is a preforeclosure the same as a short sale?
No, not necessarily, although historically the terms have been used interchangeably. A preforeclosure assumes that the borrower has been delinquent in paying his or her mortgage and the servicer/investor agrees to accept a lesser amount to avoid the time and expense of a foreclosure action. A short-sale, however, can refer to situations in which the servicer/investor of the mortgage agrees to a payoff of a lesser amount than is actually owed, even on a current mortgage, to facilitate the sale of the property to a third party.

Source: Fannie Mae HomeSaverAdvance FAQ