Lightweight refers to articles such as footwear, apparel, and accessories that are not heavy. Articles that are lightweight are easily portable and do not wear heavily upon the body.
About Running Socks:
Running socks are hosiery specially made for the athletic activity of running. Running socks are generally ankle high, or lower, and are typically made from fibers that wick moisture away from the foot. Additional features include, a thin instep, which prevents extra pressure from the tongue and lacing of the shoes, and thick padding at the bottom and toes, which helps absorb shock as well as preventing blisters that might result from the rubbing created by the sliding of the foot inside the shoe while running.