Trouser socks are a form of knee sock, typically of a thinner material than wool or cotton socks, closer to stocking material. They're an ideal solution under trousers, especially when pantyhose would add an uncomfortable extra layer. Trouser socks are available in sheer, semi-opaque and opaque weights. For classic business and traditional outfits, select trouser socks in the basic colors--skin tone, black, chocolate and off-backs or grays. Add some pizzazz with patterns or textures, like ribs, chevrons, subtle stripes or diamond patterns. Most trouser socks are made of nylon/spandex blends, with elastic around the top. You can also find them in cotton with a touch of spandex or elastane for stretch.