submillimeter wave radiation

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun astronomy Electromagnetic waves with a wavelength less than one millimeter (the band begins at about 0.3 THz). A term often used by radio astronomers.
• noun engineering Electromagnetic waves roughly in the band less than 1 millimeter in wavelength, used as a synonym for T-ray or T-wave
• noun terahertz radiation