unprecedented

American  

[uhn-pres-i-den-tid] / ʌnˈprɛs ɪˌdɛn tɪd /

adjective

1. without previous instance; never before known or experienced; unexampled or unparalleled.

   an unprecedented event.

   Synonyms:

   novel, exceptional, extraordinary, unique

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unprecedented British  

/ ʌnˈprɛsɪˌdɛntɪd /

adjective

1. having no precedent; unparalleled

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Other Word Forms

• unprecedentedly adverb
• unprecedentedness noun

Etymology

Origin of unprecedented

First recorded in 1615–25; un- ¹ + precedent + -ed ²

Example Sentences

The upcoming Vera C. Rubin Observatory in Chile will soon begin an unprecedented survey of the night sky, generating about 10 terabytes of data every night during a decade long program.

From Science Daily

Oil prices rose more than 5% on Wednesday, with most of the increase coming after The Wall Street Journal reported details of the IEA’s unprecedented market intervention plan.

From The Wall Street Journal

The union said the £580,000 decrease was unprecedented, and revealed the anger of its members a year on from the start of all-out industrial action in the city.

From BBC

The immediate scale of his wreckage was unprecedented, but so was the level of resistance from the American public — two sides, fighting like hell to be the louder one.

From Salon

The spacecraft and its twin, Van Allen Probe B, were on a mission to gather unprecedented data on Earth's two permanent radiation belts.

From BBC

Related Words

• bizarre
• extraordinary
• fantastic
• miraculous
• new
• remarkable
• singular
• uncommon
• unheard-of
• unique
• unparalleled
• unrivaled
• unusual