I've always loved the term Fat Quarter. It's a term quilters use and here's the maths that explains it.
Furnishing fabric comes in a width of 140cm - give or take. The printed area is generally 137cm. Half a metre of that is 50cm x 137cm, say, and half of that again is what those in the quilting circles call a 'fat quarter.' Honestly, it's the most useful piece of fabric in my stash, especially for making cushions and patchwork curtains.
Now you can buy handy-sized fat quarters of ClothFabric in select designs and colourways, without having to commit to a full metre.
The printed area of all our fat quarters is at least 50cm x 67cm. (if the fabric base cloth is wider you will get an extra useful strip along the selvage, like in the photo here.)