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).
Radio Waves Radio waves have frequencies ranging from 3*10 1 to 3*10 9 Hz (30 Hz to 3 GHz) and wavelengths from 10-1 m to 10 7 m (100 mm to 10,000 km). Radio waves are produced from the alternating current of an LC circuit. Radio waves carry information through modulation. Radio, television, cell phones, and remote controls all use radio waves.