Kind of curious why your Realtor didn't ask the question of the sellers agent as to what they meant by the term.
I too am SFR certified, and done several short sales, and have never seen/heard this term used before.
I suggest you ask your realtor to get to the bottom of this, just in case you or your realtor didn't get the term quite right. On the otherhand, intuitively, it sounds like you may be right and they are trying to move the case along.
I am assuming that your offer was not yet accepted by the bank, because once the contract is approved as a short sale by the bank, they typically give the buyer 45 days from acceptance to close. I would also have your realtor find out (if you don't already know ) if the bank had a BPO (broker price opinion) already performed, This is the first step in approving a short sale contract offer. It determines the house's fair market value for the bank so they can evaluate your offer and decide if your offer is good enough not to have too much of a "short" fall in proceeds at closing.