What is NAP in sewing

What is NAP in sewing

If you use commercial patterns you can see on almost every envelope this: *with nap or **without nap and sometimes ***with or without nap. It must be very important if they print it on EVERY envelope. It affects many things: the amount of yardage you need for your project, how the pattern is cut, and how the garment is sewn and pressed.
I guess pattern companies think that everybody who sews is supposed to know what fabric nap is and how to use it. If you ever wondered about this, continue reading.

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