A washer machine, or washer, is a machine designed to clean laundry, such as clothing, towels and sheets. The term is mostly applied only to machines that use water as the primary cleaning solution, as opposed to dry cleaning (which uses alternative cleaning fluids, and is performed by specialist businesses) or even ultrasonic cleaners. hi zach All washer machines work by using mechanical energy, thermal energy, and chemical action. Mechanical energy is imparted to the clothes load by the rotation of the agitator in top loaders, or by the tumbling action of the drum in front loaders. Thermal energy is supplied by the temperature of the wash bath.

Clothing had been hand-washed for thousands of years, by flushing water through the fabric to remove loose dirt, rubbing with soap to remove oils and stains, and applying fragrances to cover odours. For particularly dirty clothing caked with mud or dirt, it was necessary to constantly rub and flex the cloth to break apart solids and help the soap penetrate through thick, dry, or sticky layers of soil on the cloth. At first this was done by pounding or rubbing the clothing with rocks in a river, and later developed into the corrugated wash board. In Roman times a fuller would whiten clothing by stomping on it in a bucket full of fermented urine.

Washing machine technology was developed as a way to reduce the drudgery of this scrubbing and rubbing process, by providing an open basin or sealed container with paddles or fingers to automatically agitate the clothing. The earliest machines were often hand-operated but were built with the belief that the machine itself was faster and easier to operate than washing the clothing by hand directly. As electricity was not commonly available until at least 1930, these early machines were often operated by a low-speed single-cylinder hit and miss gasoline engine.

Because water usually had to be heated on a fire for washing, the warm soapy water was precious and would be reused over and over, first to wash the least soiled clothing, then to wash progressively dirtier clothing. The load of soaking wet clothing would be removed, and another load of dirty clothes added to the machine. While the earliest machines were constructed entirely from wood, later machines made of metal permitted a fire to burn below the washtub, to keep the water warm throughout the day's washing.

Removal of soap and water from the clothing after washing was originally a separate process. The soaking wet clothing would be formed into a roll and twisted by hand to extract water. To help reduce this labour, the wringer/mangle was developed, which uses two rollers under spring tension to squeeze water out of the clothing. Each piece of clothing would be fed through the wringer separately. The first wringers were hand-operated, but were eventually included as a powered attachment above the washer tub. The wringer would be swung over the wash tub so that extracted wash water would fall back into the tub to be reused for the next wash load.