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definitions

ultrashort

[uhl-truh-shawrt]
adjective
  1. extremely short.
  2. (of a wavelength) smaller than 10 meters.

Origin of ultrashort

First recorded in 1925–30; ultra- + short
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for ultrashort

ultrashort

adjective
  1. (of a radio wave) having a wavelength shorter than 10 metres
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012