For waist bow, the current definition in the wiki is:
"A bow that is tied around the front side of a character's waist. It should function as a makeshift belt to keep the dress around the waist. If the bow is a decorative aspect of the clothing, use dress bow instead (unless both are present).
If the bow is in the rear, use back bow instead. There are instances of both happening however, such as post #3495784."
From the name at least it would seem to cover any bow regardless of the front or the back but it's specified to be only for the front. Wouldn't a tag like front bow be more suitable for the current definition and make more sense for being the opposite of back bow?