Stature, Height
noun
Someone's back height is their height. It also refers to their stature.
せたけ
The reading comes from the vocab readings of 背 and 丈, combined together.
背丈の低い男が千鳥足でバーから出てきて、私の目の前でゲロを吐いたんです。
A short guy staggered out of the bar and threw up in front of me.