A cordless mouse, also called a wireless mouse, is a mouse that connects to a computer without the use of wires. Instead, the mouse uses some manner of wireless technology, like Bluetooth, RF, or infrared radio waves. Usually, a USB receiver is plugged into the computer and receives signals from the cordless mouse.
Note: Cordless mice needs batteries to work. Typically they use AA batteries, AAA batteries, or rechargeable NiMH or Li-ion batteries. A cordless mouse that is rechargeable requires a base station to charge the batteries in the mouse.