Why are they called vacuums?

Why are they called vacuums comes from operating principle of creating a partial vacuum to pick up dirt. The word vacuum comes from Latin vacuus meaning empty, void, or free. In physics, a vacuum is space with little or no matter and very low air pressure. A vacuum cleaner is called vacuum because it contains a motor and fan that expels air from inside chamber, lowering pressure inside and creating partial vacuum, so higher atmospheric pressure outside pushes air and dust into machine through nozzle. Early inventors in late 1800s and early 1900s, such as Hubert Cecil Booth who invented first motorized vacuum in 1901, called it vacuum cleaner to distinguish from carpet sweepers that used brushes to flick dirt, emphasizing that new machine used suction from vacuum. The name stuck because it describes mechanism rather than appearance. Even modern cyclonic vacuums still create low pressure region, so vacuum remains accurate. So they are called vacuums because they work by creating empty low pressure space that must be filled, causing suction that removes dirt from surfaces into collection bag or bin.