(aviation) A type of airline that tries to keep ticket prices as low as possible, by charging for everything, such as checked-in baggage, carry-on baggage, food, beverages, assigned seat numbers, etc.

(physics) A fault in classical physics, from the Rayleigh's Law/Rayleigh-Jeans Law outcomes at short wavelengths/high frequencies, that causes infinite amplification of shorter wavelength/higher frequency radiation inside a cavity, due to the application of equipartition theorem on black body radiation within a cavity.

(pathology) A type of ulcer caused by the bacterium Mycobacterium ulcerans.

A giant planet, of similar mass to that of Jupiter, which orbits close enough to its sun to become tidally locked, and whose day-side atmosphere has therefore heated up so much, as to break apart most molecules, leaving atomic gas. The day-side atmosphere has the temperature and spectral characteristics of a star's surface.

plural of Ulam spiral

(mathematics) A graphical depiction of the set of prime numbers, constructed by writing the positive integers in a square spiral and specially marking the primes.

Alternative spelling of ultrarich (any sense).

Alternative spelling of ultrarich.

Alternative form of ultrarich (any sense)

Alternative form of ultrarich