Electromagnetism is the magnetic effect caused by electricity in conductors. That is electric conductors behave as magnets when current is passing through them, and create a magnetic field around them.
Equally, when a conductor moves in a magnetic field, then an electro magnetic force (potential difference ) is developed across the ends of the conductor. This is also due to the phenomenon of electromagnetism.
Electromagnetism is the conversion of electric energy into magnetic flux (potential) energy and magnetic potential energy in to electric energy in the form potential or flow of current.