diagnostic

American  

[dahy-uhg-nos-tik] / ˌdaɪ əgˈnɒs tɪk /

adjective

1. of, relating to, or used in diagnosis.

2. serving to identify or characterize; being a precise indication.

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noun

• diagnostics
  plural

1. diagnosis.

2. a symptom or characteristic of value in diagnosis.

3. Medicine/Medical. a device or substance used for the analysis or detection of diseases or other medical conditions.

4. Computers.

   1. a message output by a computer diagnosing an error in a computer program, computer system, or component device.

   2. a program or subroutine that produces such messages.

diagnostic British  

/ ˌdaɪəɡˈnɒstɪk /

adjective

1. of, relating to, or of value in diagnosis

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noun

1. med any symptom that provides evidence for making a specific diagnosis

2. a diagnosis

Other Word Forms

Derived Forms

• postdiagnostic
  adjective
• prediagnostic
  adjective
• diagnostically
  adverb

Inflected Forms

Nouns

• diagnostics
  plural

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.

Example Sentences

See Examples For:

diagnostic diagnostics

Wall Street analysts have speculated that rival diagnostic companies such as Natera or Guardant Health could be among the interested parties.

From The Wall Street Journal ● Sep. 4, 2026

The company rebranded from Tempus Labs to Tempus AI ahead of its 2024 IPO, perhaps hoping it could be valued as a technology company rather than a diagnostic lab.

From The Wall Street Journal ● Sep. 4, 2026

Nora explains to the counselor running a workplace mental health seminar that the Greeks viewed anger as a kind of insanity, but with different diagnostic profiles.

From Salon ● Sep. 3, 2026

An international team of researchers, working closely with scientists at the universities of Zurich and Greifswald, has developed and validated a diagnostic scoring system designed to identify Takotsubo syndrome before cardiac catheterization is performed.

From Science Daily ● Sep. 2, 2026

Then, they had me run a full diagnostic on the MAV.

From "The Martian" by Andy Weir

The study, published in European Urology Oncology, was led by the University of Birmingham and a diagnostics company Nonacus, and involved nearly 1,000 patients at seven hospitals in England and Scotland.

From BBC ● Sep. 2, 2026

The industry saw a large private-equity deal earlier this year, when Blackstone and TPG took women’s-health diagnostics company Hologic private in April in a deal valued up to $18.3 billion, including debt.

From The Wall Street Journal ● Jul. 31, 2026

“AI-driven drug discovery, clinical development and diagnostics are beginning to improve productivity across the sector, while life science tools appear to be emerging from a multiyear destocking cycle.”

From MarketWatch ● Jul. 15, 2026

"Innovations in imaging hardware have the potential to transform diagnostics, and this study is an important step toward next-generation MRI technology," says Dr. Ebba Beller, a co-author of the paper at Rostock University Medical Center.

From Science Daily ● Jul. 10, 2026

Perhaps I was nothing more than a victim of modern diagnostics; in another century it would have been said of me that I was old and therefore losing my mind.

From "Atonement" by Ian McEwan