This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

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.

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

"Clonidine and naloxone in ultrashort opiate detoxification."

ultrafast    hypershort    supershort   

quantumcascade    picosecond    circularly-polarized    tight-beam    short-duration