Selvage is the finished lengthwise edge of a woven fabric. Straight grain or lengthwise grain refers to the fabric threads running parallel to the selvages. Bias grain is the diagonal direction at a 45 degree angle. Nap is when a fabric has a one-way design, texture or subtle variations in color depending on the direction they are held. All panels must be cut running in the same direction.
Repeat is one pattern or motif printed on the fabric.
Railroading fabrics is when the fabric is turned on its side so that the width becomes its length. This is used to eliminate seams for sewing valances, cornices or ruffles. When measuring for yardage requirements, round up your measurement. It is always a good idea to purchase a little extra fabric, just in case. Any leftovers can be sewn up as room accents.