This is in reply to @Matt S
Okay. I am defering to you for the printed explanation, and to myself for the actual doing. And they appear to differ.
My end goal is to get a pant that sits at true waist - - - to me that's my tummy button - - - without junk being compressed or fabric clinging to the cheeks. To achieve that, each inseam is slit open at the crotch for a distance of between 3 to 5 inches and a triangular wedge of compatible fabric inserted. This forms a pouch, essentially unnoticed due to its location, in which the lower part of the valuables rest, while at the same time granting ease to the cheeks.
I have heard of rise being described as you say, outseam minus inseam, but I've never measured out seam, don't even know what my inseam is because, after releasing the crotch as described and putting on the pants, a full length mirror is hauled out, stood in front of side-to and the pant bottom is folded up until it is 2 I/4 inches from the floor (I am in stocking feet and holding a measiring stick with 2 1/4 inches marked off at the end, in a thick line so it can be seen in the mirror without bending or any movent, having adjusted the fabric at leg's end multiple times until the folded-up end meets the measuring line.) Then a chalk mark is made signifiying the proper end to the finished leg. This differs from pant to pant which is why I don't know my inseam, just that when finished, the leg bottom sits 2 1/4 inches from the floor, a measurement unique to me, because when shorn, the break will be precisely where I want it. (Recommended to others as it yields a break, but miniscule.)
So there you have it. A pant that can be cinched at true waist without discomfort or unsightly bulges, yet have the proper length, look good, fall well, no friction at crotch while standing or walking. And I have always referred to this as high rise