ultra

¹ American  

[uhl-truh] / ˈʌl trə /

adjective

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

---

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 ).

---

ultra ¹ British  

/ ˈʌltrə /

adjective

1. extreme or immoderate, esp in beliefs or opinions

---

noun

1. an extremist

ultra- ² British  

prefix

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

   ultramicroscopic

2. extreme or extremely

   ultramodern

---

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

These ultra thin materials are known to behave very differently from their thicker, three-dimensional versions.

From Science Daily

The new metasurface takes the form of an ultra thin chip covered with tiny structures that are smaller than the wavelength of light itself.

From Science Daily

The company significantly expanded its offerings in 2025 “to give members access to investment tools traditionally reserved for the ultra wealthy,” Noto said.

From Barron's

WASP-121b belongs to a class of planets known as ultra hot Jupiters.

From Science Daily

She said the plasterer, from Bolton, Greater Manchester, was due to climb Yr Wyddfa twice in one day as part of his training for an ultra marathon the following weekend.

From BBC