When you want to cover your legs, whether with socks or tights, what you need is hosiery. Shopping for stockings? Just ask the salesclerk, "Which way is the hosiery department?"
Hosiery is a fairly old-fashioned word for socks and stockings as a group. You'll still see it in some department stores that have an entire section dedicated to foot- and leg-covering garments, although sometimes it's called "legwear." Hosiery comes from an even more old-fashioned word, hosier, "maker or seller of hose."