from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Of or relating to radio waves with a wavelength less than 10 meters (33 feet).
- adj. Of extremely short duration: an ultrashort flash.
- adj. Extremely short: an ultrashort skirt.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Extremely short in duration, typically on the femtosecond scale
- adj. Having a wavelength of between 1 and 10 metree
- adj. Having a very short term of investment, typically less than a year
- n. A bond with an extremely short term, typically less than a year
ultra- + short (Wiktionary)