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).
They do not require a medium to travel through. A radio wave is composed of an electrical wave, and a magnetic wave. The 2 waves travel together, creating each other as the wave travels through what ever medium it is in, be that air, wire, or what we call space. kerry k Â· 10 years ago.