What is a Fat Quarter?

Have you heard someone refer to a "Fat Quarter" and wasn't sure what they were talking about?  Well, along with a couple of other Quilting Terms,  Fat Quarters came about as a great marketing tool for selling more fabric.  

A fat quarter of fabric is a one-fourth yard cut that usually measures 18" x 22"*. To create a fat quarter, cut a half-yard of fabric, 18" ​along the fabric's lengthwise grain, then cut that piece in half at its midpoint as illustrated..   Fat quarters are sold individually or packaged in a bundle.