Brushed motors are one type of motor commonly found in Antweights. They are usually used for drive, whereas the other type of motor (brushless) are used for weaponry.
Brushed motors use physical contacts, called brushes (hence their name) that press against the commutator of the motor which supplies the power to make the motor turn. The motors themselves have two wires coming out (positive and negative) allowing you can make them spin round by connecting these wires to the correct terminals of power supply.