The gap, big enough to securely store a potato, created by misfitting jeans when the waistband does not meet one's back due to being disrupted by an especially convex badonk. The bane of existence to pants-wearing bedonked folk, it can be measured by the number of potatoes one can store in the consolingly handy storage space. The variety of said potatoes is entirely up to the interpreter's imagination.
Jane: I really like these jeans, but they just don't fit!
John: But they have to fit -they're in your size and everything.
Jane: Nope. Too much potato room.
Jane: Damn my deliciously plump ass.