A term to describe when a persons thigh and butt is not distinguisable. This is caused by either fat thighs or a flat butt.
google search: butthigh.
A fat person with rolls under their butt, which makes it hard to tell where the butt ends and the thigh begins.
A skinny person with a small flat butt, which makes the whole backside look like a flat brick.
A lack of definition in the glutular region, commonly seen as an almost imperceptible transition between butt and thigh. Often the butt and thigh may appear to be a single, amorphous shape. (pronounced buh-thigh)
Every time Kaitlin "accidentally" changes in front of me, I am lucky enough to see what a buthigh looks like unhindered.