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.
For comparison, £25m is the amount ministers plan to spend on surgical and diagnostic hubs.
From BBC • Jul. 1, 2026
With a digital health record, doctors and their AI-driven diagnostic tools could have full visibility into a patient’s health history.
From MarketWatch • Jun. 27, 2026
A T-score between –1.0 and –2.5 indicates osteopenia, while a T-score below –2.5 meets the diagnostic threshold for osteoporosis.
From Science Daily • Jun. 25, 2026
Available tests would yield a diagnostic guess by ruling out other causes, such as strokes, tumors or bleeds in the brain.
From The Wall Street Journal • Jun. 20, 2026
"I am now doing a diagnostic on the reactor. I am thinking that Johanssen is busy with the launching training. So perhaps I do this diagnostic for her."
From "The Martian" by Andy Weir
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.
