What does the unit '3 ounces' mentioned in the coat description measure?

Although a number is attached, it is hard to tell from the notation alone whether it refers to weight or thickness. The CURLY FUR COAT from Low Tide has its lining quilted with 3oz padding^[1].

An ounce is originally a unit of weight, and an ounce attached to padding usually refers to how much cotton filling weighs per a certain area. Therefore, for the same type of cotton filling, a higher number means more amount is added so it becomes thicker, while a lower number means a thinner and lighter finish. It is a notation indicating the amount of cotton filling inside, rather than a value referring to the thickness or material of the outer fabric.

The quilting mentioned alongside is a method of placing that cotton filling between two layers of fabric and stitching it at regular intervals to secure it. If left alone, cotton filling shifts and clumps to one side while wearing and washing, but the stitch lines divide compartments to prevent that movement. Having 3oz and quilting written side by side indicates in a single line how much the lining is filled and how it is held in place^[2].