This email from Sundance says: "Congratulations! Your submission [name of screenplay] has been chosen by our selection committee for the next round of the review process. Please send your completed script to the Sundance Institute Office, etc."
The small print at the bottom says: "There is not an official name/designation to this part of the application process. We see it strictly as the next step. We do not give it the title of Second or Final round, Finalist, or Semi-Finalist."
I guess they don't want you to jump the gun and go patting yourself on the back or prematurely calling yourself something impressive. As you may have guessed, my script wasn't chosen. (I did receive a very nice rejection, but it's too detailed to post, since now I understand that I have to protect myself from getting blacklisted from the movie industry, as well as the literary world.)