Underlining: lining used to add body to a garment.
Understitching: Keeps fabric or lining from rolling onto the right side of the garment. After pressing the seam allowance and facing away from the garment, stitch through both a scant 1/8" from the seam. Some people grade (trim in incremental heights) the seam allowance and facing/lining.
Universal Needle: A slightly rounded tip to use for woven or knit fabrics. It is perferred to use a regular needle for wovens and a ball point needle for knits.
View: Most patterns show different variations on the pattern package. Each variation is called a view.
Walking foot: A special foot attachment for sewing a macine that allows for sewing through several layers of fabric without shifting the lower fabric and the upper fabric. Good also for sewing slipper (silk, rayon, ect.) Fabrics.
Warp: Threads running the lenght of a woven fabric. ALso know as the lengthwise grain little to no stretch about 90 from the weft an d 45 degrees from the bias.
Wearable art: Decorative, usually quilled, clothing made the unique, beautiful, and functional.
Whip Stitch: A simple running stitich used to hold together two pieces of fabric. Good for closing seams of leather, crochet/knit item, or the opening of a pillow that has been stuffed.