diagnostic
Americanadjective
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of, relating to, or used in diagnosis.
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serving to identify or characterize; being a precise indication.
noun
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a symptom or characteristic of value in diagnosis.
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Medicine/Medical. a device or substance used for the analysis or detection of diseases or other medical conditions.
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Computers.
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a message output by a computer diagnosing an error in a computer program, computer system, or component device.
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a program or subroutine that produces such messages.
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adjective
noun
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med any symptom that provides evidence for making a specific diagnosis
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a diagnosis
Other Word Forms
Derived Forms
Etymology
Origin of diagnostic
1615–25; < Greek diagnōstikós, equivalent to diagnōst ( ós ) distinguished (akin to diágnōsis; see diagnosis) + -ikos -ic
Explanation
Anything diagnostic has to do with disease, especially figuring out which one a patient has. If your doctor wants to run diagnostic tests, then she isn't exactly sure what's wrong with you — so the tests will help diagnose you (figure out what's wrong). The TV show House is all about diagnostic tests: it features illnesses that are unusual and hard to determine. But anything diagnostic is trying to figure out what's wrong. A writing test could be called diagnostic if it's trying to determine how good or bad your writing skills are.
Vocabulary lists containing diagnostic
Novel Study: The Crucible, Act 1
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The Wednesday Wars
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Lesson 1
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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.
Jobs can be complex, which is why some companies charge an “investigation” or diagnostic fee.
From MarketWatch • Jun. 10, 2026
The three-page memo provides an overview of Trump's physical examination and diagnostic testing, in which Barbabella concludes that the leader is "fully fit to carry out all duties of the Commander-in-Chief and Head of State."
From Barron's • May 30, 2026
The new faculty letter says that “for three consecutive years, 20-30% of UC Berkeley first-semester calculus students who participated in mathematical diagnostic testing displayed severe preparation deficits.”
From The Wall Street Journal • May 28, 2026
The program aims to combine immunology and related research fields to develop new diagnostic tools and personalized medical treatments.
From Science Daily • May 28, 2026
For my annual physical in 1972 he used diagnostic methods popular back in medical school in 1910.
From "Middlesex: A Novel" by Jeffrey Eugenides
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.
