In RTK1 this is written for this kanji:

This character, used for everything from little humps of hills to camel humps, easily suggests the hunch on the pig?s back and
hind parts where the best cuts of meat are to be found (and
hence the English expression for luxury, ?living high off the
hog.?) The elements we have to work with are: pinnacle . . .
walking legs . . . cell. [11]

but..when I looked up the kanji to find what words its in, I did not find ANY words dealing with "hump." They are almost all something to do with "prosperity." Why did heisig write this???

Prosperity is a better meaning... but here's a couple words hump kinda works with:
隆起 【りゅうき】 (n) protuberance, projection, rising, (P)
膨隆 【ぼうりゅう】 (vs) swelling up

hmm yeah i guess that works there. as always, i make sure to double check the definitions in RTK as they are sometimes very misleading.