shortwave

Short definition from Wiktionary

Adjective

1. 1
   Having a wavelength of approximately 10 to 100 meters.
2. 2
   Capable of transmitting or receiving signals at such a wavelength.

Noun

1. 1
   An electromagnetic wave having a wavelength between approximately 10 and 100 meters, corresponding to frequencies between 3 and 30 MHz.
2. 2
   Any frequency in this range, especially when used in broadcasting.
3. 3
   Downward radiation entering the earth's atmosphere that is in the shortwave frequency range.