To an extreme degree; very
an ultra-conservative politician
Extremely fine in size, texture, composition, etc.
Beyond one’s legal power or authority
Extremely modern; advanced
this computer is a high-performance ultra-modern machine
A very broad bandwidth; (in later use) specifically a radio communications technology which uses the transmission of very narrow and low-energy pulses over a broad bandwidth to achieve high communication speeds; frequently attributive.
The highest point or culmination (of).
The perfect or most extreme example of its kind; the ultimate
jeans were the ne plus ultra of the modish and modern
A radio frequency in the range 300 to 3,000 MHz
(Of a neutron) having an energy of the order of 10−7 eV or less
(Of radio waves) having a wavelength significantly shorter than that of the usual short waves, in particular shorter than 10 metres (i.e. of a VHF frequency above 30 MHz)
(Of electromagnetic radiation) having a wavelength shorter than that of the violet end of the visible spectrum but longer than that of X-rays
The sport or activity of competing in ultramarathons
Extremely critical or judgemental
Filtration using a medium fine enough to retain colloidal particles, viruses, or large molecules
A long-distance running race that is longer than a marathon (which is strictly 26 miles 385 yards/42.195 km)
A type of laptop computer that is very slim and lightweight
A person who is extremely conservative in politics or religion
Too small to be seen by an ordinary optical microscope
Extreme nationalism that promotes the interest of one state or people above all others