ultra

¹ American  

[uhl-truh] / ˈʌl trə /

adjective

1. going beyond what is usual or ordinary; excessive; extreme.

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noun

1. an extremist, as in politics, religion, fashion, etc.

2. Military. Ultra, the British code name for intelligence gathered by decrypting German wireless communications enciphered on the Enigma machine during World War II.

ultra- ² American  

1. a prefix occurring originally in loanwords from Latin, with the basic meaning “on the far side of, beyond.” In relation to the base to which it is prefixed, ultra- has the senses “located beyond, on the far side of ” (ultramontane; ultraviolet ), “carrying to the furthest degree possible, on the fringe of ” (ultraleft; ultramodern ), “extremely” (ultralight ); nouns to which it is added denote, in general, objects, properties, phenomena, etc., that surpass customary norms, or instruments designed to produce or deal with such things (ultramicroscope; ultrasound; ultrastructure ).

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ultra ¹ British  

/ ˈʌltrə /

adjective

1. extreme or immoderate, esp in beliefs or opinions

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noun

1. an extremist

ultra- ² British  

prefix

1. beyond or surpassing a specified extent, range, or limit

   ultramicroscopic

2. extreme or extremely

   ultramodern

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Etymology

Origin of ultra¹

Independent use of ultra-, or shortening of words prefixed with it

Origin of ultra-²

From Latin ultrā (adverb and preposition) “on the far side,” derivative of ulter (unrecorded) “located beyond”

Example Sentences

The team focused on ultra thin films made from two elements, tellurium and selenium.

From Science Daily • Feb. 25, 2026

“Ya boy is going to go into ultra grind mode and make the greatest content of my life in 2026,” he wrote.

From The Wall Street Journal • Jan. 3, 2026

The current ultra modern era evolved the market into investments, scarcity, and digitized the business with websites like Arena Club, which repackages pre-graded cards as slab packs.

From Los Angeles Times • Dec. 26, 2025

Credit cards and new financial technologies made that easily accessible, and ultra low interest rates made borrowing cheap.

From Barron's • Dec. 18, 2025

A year later Joseph Glanvill published Plus ultra: or the Progress and Advancement of Knowledge since the Days of Aristotle.

From "The Invention of Science" by David Wootton