How can a person possibly mistake what she is wearing for thighhighs? *fixes tag and shakes a fist towards the tagger*

Given pantyhose are, design-wise, an evolution of stockings I can't blame folks who confuse the two.

For this image, the poster probably tried to add the now obsolete tag stockings to describe her legwear. Of course, calling them stockings is completely wrong which SO MANY people tend to do (Biggest offenders: English and Japanese).

Probably because stockings is a vague word that most people don't use very often.