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• ultra
  ultra

  adjective

  going beyond what is usual or ordinary; excessive; extreme.
• ultra-
  ultra-

  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 ).

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”

Explanation

Use the adjective ultra to describe something extreme, like your ultra strict parents or your own ultra radical political views. If your sister is ultra uptight and your English teacher's syllabus is ultra traditional, it means that both of them hold unusual opinions, far outside of the normal range. Neither would be a good fit for your own ultra relaxed philosophy of life. Ultra means "beyond" in Latin, and its meaning of "outside the norm" comes from the French word ultra-royaliste, or "extreme royalist." Eventually, it was shortened to just ultra, to describe any extreme opinion.

Example Sentences

Coastal desalination plants discharge ultra salty brine waste that can harm marine life, but the undersea pods release a less concentrated brine, which the company says is friendlier to the ecosystem.

From Los Angeles Times • Jun. 2, 2026

Together, the SLB portfolio of products allows oil and gas producers to target technically complex ultra deep water and offshore reserves as efficiently as possible.

From Barron's • May 28, 2026

“We continue to work closely with Airbus on the delivery and certification process that will enable us to begin operating these history-making ultra long-haul flights,” the spokesperson said.

From The Wall Street Journal • May 26, 2026

The advance could support ultra efficient information processing technologies, create new opportunities in quantum optics, and expand the capabilities of super resolution imaging.

From Science Daily • May 21, 2026

One of Galileo’s opponents, Lodovico delle Colombe, complained in 1610/11 that Galileo behaved like someone setting sail on the ocean, heading out past the Pillars of Hercules and crying, ‘Plus ultra!’

From "The Invention of Science" by David Wootton