The definition of an electromagnetic wave is one that moves by the power of electric and magnetic fields.
An example of an electromagnetic wave is what provides the power in a microwave.
A wave of electromagnetic energy that is radiated by an accelerating or oscillating electric charge and propagates through a vacuum or a material medium as a periodic disturbance of the electromagnetic field at a frequency within the electromagnetic spectrum.
A wave propagated through space or matter by oscillating electric and magnetic fields: in a vacuum it travels at the speed of light.
A wave of energy consisting of electric and magnetic fields, oscillating at right angles to each other.