wheel

views updated

wheel Circular structure that revolves around a central axis. Before the wheel was invented, heavy loads were sometimes moved by rolling them on logs or on rounded stones. More than 5000 years ago, sections of tree trunks were cut to form the first wheels for carts. Spoked wheels were introduced several hundred years later. Eventually, the wheel was used in simple machines, such as the waterwheel and potter's wheel.

More From encyclopedia.com