Units sold through would be my guess. This was at the end of the montage right before Layden came out on stage and said PS4 is the fastest selling console of all time.
Think about it this way. At the end of September they had shipped 13.5 million. They probably had under 500k on shelves. 14,088,511 sold through is probably at the end of October. Just add November's numbers and (about 2.5 million) 1 week of December and you are pushing above 17.5 million easy. Xbox One has to be at 9.4 at the very least and Wii U is simply overtracked for posterity.