Fabric selvage is the tightly woven edge that runs along each side of a piece of fabric’s lengthwise grain, which is also called the fabric’s warp. Selvage edges can be seen on the edges of quilting fabric that are at the top and bottom of a bolt of fabric. In Great Britain, the same term is often spelled “selvedge.”
The word ‘selvedge‘ relates to the ‘self-edge’ of fabric. Selvedge is woven so the fabric’s ‘edge’ can be used in garment construction. … See a finished selvedge jean. The edges of the outseam, shown when cuffed, identify selvedge denim.
The grainline that you will see most often when cutting out your pattern is the one that runs parallel to the selvage. To find this lengthwise grain of your fabric, line up the selvages with right sides together. The raw edges cut from the fabric store will most likely not line up as they did before washing.
In textile terminology, threads that run the length of the fabric (longitudinally) are warp ends. Threads running laterally from edge to edge, that is from left side to right side of the fabric as it emerges from the loom, are weft picks. Selvages form the extreme lateral edges of the fabric and are formed during the weaving process. The weave used to construct the selvage may be the same or different from the weave of the body of the fabric cloth. Most selvages are narrow, but some may be as wide as .75 inches (19 mm). Descriptions woven into the selvage using special jacquards, colored or fancy threads may be incorporated for identification purposes. For many end-uses the selvage is discarded. Selvages are ‘finished’ and will not fray because the weft threads double back on themselves and are looped under and over the warp..