The girth of something is the distance around its middle, and it usually refers to a person’s waist. If you get pregnant with twins your girth will probably block your view of your toes.
One can measure the girth — diameter of the mid-section — of an airplane, tree trunk, or anything cylindrical, but it most often describes a large human waist. A rail-thin person doesn’t have a “minuscule girth ,” but when Aunt Velma has her seventh helping of lasagna and has to unbuckle her belt, her girth has outsized her attire. As a noun, girth is a strap that encircles the belly of a horse, mule, or other animal to secure a load.
