2. The process of spreading to a larger area or greater number; dissemination. 3. Physics The act or process of propagating, especially the process by which a disturbance, such as the motion of electromagnetic or sound waves, is transmitted through a medium such as air or water.
How do waves propagate through space?
Propagation of an Electromagnetic Wave. Electromagnetic waves are waves which can travel through the vacuum of outer space. Mechanical waves, unlike electromagnetic waves, require the presence of a material medium in order to transport their energy from one location to another.