- (finance) Having a very short term of investment, typically less than a year
"an ultrashort bond"
- (physics, of a wave) Having a wavelength of between 1 and 10 metres
- (sciences) Extremely short in duration, typically on the femtosecond scale
"an ultrashort pulse"
- Very short.
- (finance) A bond with an extremely short term, typically less than a year