Well I now know what WOF stands for -the width is selvage to selvage

The selvedge question is answered, but you need to know that things that say a time...like the 10 minute table runner ALWAYS take me about three times longer. Or does that 10 minutes mean just the sewing time? But that's for another day.

Thank you everyone for all the great information. I made the pillowcase, it only took me two HOURS!! and the pillowcase is so long that I need to buy a king size pillow to fill it up. I evidently measured something wrong, maybe loaf instead of wolf, lol.

I love/hate auto correct, it should say length of fabric (loaf) and width of fabric (wolf)

I've made these pillowcases and, yes, takes me more than 20 minutes. I count the cutting, sewing, and pressing in the "time." When sewing up the side and end seams, I use the French seam, which is sewing the seams with the wrong side to wrong side together, trim seam to a little less than 1/4 inch and then pressing with right side to right side to sew the 1/4 inch seam on the inside These made great kids' pillowcases because they are so durable. Our great grands love them pillowcases for their room. The last ones I made were monster trucks and Superman.

This may eve be more confusing for you, but I trim my pillowcases down to 21" from the fold cutting off the salvages. Just easier to cut 21" than 42". I make pillowcases to go with my quilts for foster kids. Here is one that just needs the seams sewn:

This is like Kay Wood's 6-hour quilt--took me days as I kept changing fabrics. I use a serger on my pillowcases -- serge across the top and down the sides of the main piece. Serge the bands into a circle and then do a serge putting all three parts together--no seams to show on the side.

I was always told the only dumb question was the one not asked. If you don't ask, you don't know. If you have two selvage edges, all of the fabric from one salvage to the other one is WOF, if its folded in half then it'd be 1/2 WOF. It usually is side to side, depending on the pattern or design on fabric.