Thighhighs are distinct from pantyhose, which are made of a sheer fabric that covers everything from waist to toe. Another distinguishing factor is that thighhighs are able to stay up by themselves (at the top there's usually some sort of elastic band or other material to hold them in place) whereas stockings require the use of a garter belt in order to stay up (even though they are the same length as thighhighs).
