A greeting that has extra letters in it.
If you're going to shorten "What is" so much, why not just keep going and get rid of everything except the "s"?
* A perfectly compact way to ask how someone is.
And/or to order them to eat a late meal.
And/or to describe the direction of where the moon is (indicating that it's time to eat that late meal, after which you can then ask them how they are, all with the same word**).
** The answer is "I have enjoyed my meal, but not that you ordered me to have it. Also, I already knew where the moon was."