育克,外来语，英文名yoke，也称约克
http://baike.baidu.com/view/2842610.htm
http://www.oki-ni.com/page/anatomyofajean

contoured 塑形

reverse yoke = 换向育克

Instead of the V-shape, it becomes inverted V
You can check its description & picture below:
We added a reverse yoke to the rear of the pants. Traditional jeans are cut to only add room in the center rear of the pant to allow your rear to fit. Unfortunately, most of our rears are actually two parters: you don't need more fabric in the center, you need it on either side. By reversing the yoke, a technique inspired by mountain biking shorts, we were able to shape the fabric around the rear in a way that both looked better and moved better.
http://www.core77.com/blog/case_study/case_study_outlier_on_...
http://shop.outlier.cc/shop/retail/Slim-Dungarees.html