From Simple Modern Sewing:
Each of these skirts has its own unique silhouette, and all of them have a yoke, a fashion detail that makes any waistline look trim. The yoke is a fitted panel that extends across the top of the hips. Yokes are easy to sew, and they eliminate the need for a waistband or darts. It's also easy to add pleats or tucks below the yoke to vary the style.