Broadcasting] Radio frequencies that are higher than middle and longwaves. Much of the energy in shortwaves waves tends to bounce off an ion barrier in the sky and to some extent bounce off the ground making calculated use of the bounces an effective means of long distance communication. Shortwaves were named in the early days of radio; now there are much shorter waves; VHF, UHF, and more. Those are too short to bounce off the sky. They pass through the ion barrier and are thus more efficient with directional antennae that keep the energy from going upward, they also penetrate moisture in the atmosphere. Read more here.

(or Shortwave Trough) - a disturbance in the middle or upper part of the atmosphere which induces upward motion ahead of it

A disturbance in the mid or upper part of the atmosphere which induces upward motion ahead of it. If other conditions are favourable, the upward motion can contribute to thunderstorm development ahead of a shortwave.

Lasers or LEDs that emit light with wavelengths around 780 nm or 850 nm. When using multimode fibre (50 nm), shortwave lasers can be used with FC links less than 500m. To achieve longer lengths, single-mode fibre is required. The preferred fibre core size is 50 micron as this fibre has large bandwidth so that the distance is limited by the fibre attenuation. A 62.5 micron core size is also supported for compatibility with existing FDDI installations. Fibre of this type has smaller bandwidth and, in this case, the distance is limited by the fibre bandwidth.

Refers to length of the wave or frequency in the spectrum of light. 780 nm is the operating range of short wave lasers, while 1300nm describes the range of long wave lasers.

Electromagnetic radiation generally defined as having a wavelength shorter than 4.0 microns.

A form of high- frequency current used in permanent hair removal.

Colloquially, the high frequency (HF) band between 3 MHz and 30 MHz. "Shortwave" is not a term officially recognized by the international telecommunications community.

A band of frequencies roughly between 1.5 and 30 Megahertz