-The Ask.com definition is:

A short sale is when a seller arranges with their mortgage company to sell their house for less than the amount they owe for the property. Usually the lender will forgive the rest of the loan.

-The Wikipedia.org definition is:

A short sale is a sale of real estate in which the proceeds from selling the property will fall short of the balance of debts secured by liens against the property, and the property owner cannot afford to repay the liens’ full amounts. Whereby the lien holders agree to release their lien on the real estate and accept less than the amount owed on the debt. Any unpaid balance owed to the creditors is known as a deficiency. Short sale agreements do not necessarily release borrowers from their obligations to repay any shortfalls on the loans, unless specifically agreed to between the parties.