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
Inflected Forms
Nouns
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.
Diagnostic fees cover time, labor and materials, as well as the expertise required to identify the source of a problem.
From MarketWatch • Jun. 10, 2026
Diagnostic tools are calibrated on the relative harm of different errors.
From Salon • May 12, 2026
Victor and Moses went through another Nairobi clinic, Universal Trends Medical and Diagnostic Centre, which declined to tell AFP the number of individuals referred by Global Face Human Resources.
From Barron's • Feb. 9, 2026
Diagnostic accuracy varied based on patients' self-reported race, gender, and age.
From Science Daily • Dec. 17, 2025
Wayne Grody, director of the Diagnostic Molecular Pathology Laboratory at the University of California, Los Angeles, was once a fierce opponent of consent for tissue research.
From "The Immortal Life of Henrietta Lacks" by Rebecca Skloot
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.
