"Lightweight" refers to an object or material that has a low weight compared to its size or volume. This term is often used in various contexts, such as in sports, where athletes like boxers or wrestlers compete in weight classes. For example, a lightweight boxer typically weighs less than 135 pounds, allowing for faster movements and agility. In materials science, "lightweight" describes substances that provide strength without adding significant weight. Examples include aluminum and carbon fiber, which are commonly used in industries like aerospace and automotive. These materials help improve fuel efficiency and performance by reducing the overall weight of vehicles and aircraft.