unprecedented
Americanadjective
adjective
Other Word Forms
Etymology
Origin of unprecedented
Explanation
Something that is unprecedented is not known, experienced, or done before. If you've never gone on a family beach vacation but you're planning one now, you could refer to it as an unprecedented decision. The root of this word is precedent, a noun referring to something done or said that is used as an example to be followed in the future. In law, a precedent is a legal decision that is used as a standard in future cases. So the adjective unprecedented, meaning "having no precedent," was formed from the prefix un- "not," the noun precedent, and the suffix –ed "having."
Vocabulary lists containing unprecedented
The SAT: Words to Capture Tone, List 5
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The New SAT: Words to Capture Tone
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Fast Food Nation
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
New instruments are now capable of measuring the universe with unprecedented accuracy.
From Science Daily • Mar. 30, 2026
Over the past decade, Gaia has logged such data for more than 1 billion stars across the Milky Way with unprecedented accuracy.
From Science Magazine • Dec. 29, 2023
The new satellite is expected to have unprecedented accuracy.
From Washington Times • Nov. 21, 2020
An introduction to the mission to measure distances and positions of stars with unprecedented accuracy.
From Textbooks • Oct. 13, 2016
His efforts introduced an unprecedented accuracy in astronomical and other nautical clocks.
From "Cosmos" by Carl Sagan
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
