Pouch inlet = top of pouch where stool enters
Pouch outlet = bottom of pouch where stool exits.
Every set of scope pics I have received have used those terms for at least the past 10 years.
The inlet is the area that is commonly strictured due to backsplash stool/no backsplash valve being present in the pouch as there was in the colon's inlet from the ileum before colectomy. The outlet would more likely be strictured due to inflammation in the cuff or cuffitis.