When I made ammedments to the Wiki for stockings, thigh highs, pantyhose, corset and bustier's they were all discarded and changed back to their original definitions a few hours later. Obviously a few of you saw the wiki entries I made which were much more detailed that what is currently there.
While stocking and thigh highs are (generally) the same length, and their tops are mid thigh; thigh highs cannot be considered stockings by definition, only by relative placement on the body. A thigh high has an elastic band at the top in which to keep tension around the leg making them self supportive. They are worn without a garter belt or any other garment that has garter straps.
Stockings on the other hand don't have this elastic band, rather a thicker material (than the rest of the stocking) to attach the garter clasp to. Without a garter belt, corset or bustier to attach a garter to the stockings, they will just fall down the leg as they have no means of supporting themselves. Despite their similar appearance, they are two completely different types of hosiery.
I can understand the alias of stockings -> thighhighs from an administrative point of view; distinguishing between the two can be tough if one doesn't know the differences. Conversely as an user it is frustrating that in order to find any images w/stockings the only way is to use the garter_belt tag (which is frequently missed or ignored). For accuracy's sake a thighhigh != stockings, if the alias is removed I wouldn't mind personally going through all the thighhigh tags and correctly labeling them (I have an abundance of free time). Since panties also have subsets: thong, g-string, and bikini; why can't hosiery have the same level of distinction?