1. See upright. 1. horizontal. 1  being in a position or direction perpendicular to the plane of the horizon; upright; plumb. 2  of, pertaining to, or situated at the vertex. 3  Anatomyof or pertaining to the cranial vertex.
Last Updated: Radio wave, wave from the portion of the electromagnetic spectrum at lower frequencies than microwaves. The wavelengths of radio waves range from thousands of metres to 30 cm. These correspond to frequencies as low as 3 Hz and as high as 1 gigahertz (109 Hz).
Rather, we are talking about the waves that transmit radio signals. The main difference between radio waves and sound waves is that radio waves are a type of electromagnetic wave that can travel when there is no medium, whereas sound waves are a type of mechanical wave that cannot travel if there is no medium. What are Radio Waves. Radio waves are electromagnetic waves. These are waves composed of electric and magnetic fields, which are oscillating at right angles to each other. The energy of an electromagnetic wave propagates at a direction at right angles to the oscillations in both the electric and magnetic fields.