Bias

The bias of a woven fabric runs at a 45-degree angle to the selvage and has significant stretch compared to the lengthwise or crossgrain directions. Bias edges are prone to distortion if handled carelessly — pulling, pressing while wet, or sewing without support can cause stretching that distorts the cut shape. Quilters avoid placing bias edges on the outer edges of blocks or quilts when possible. However, bias is intentionally exploited in bias binding (which curves smoothly around rounded corners) and in bias stems for appliqué.