diagnose

American  

[dahy-uhg-nohs, -nohz, dahy-uhg-nohs, -nohz] / ˈdaɪ əgˌnoʊs, -ˌnoʊz, ˌdaɪ əgˈnoʊs, -ˈnoʊz /

verb (used with object)

• diagnoses,
  present (3rd person singular)
• diagnosed,
  past participle,  past
• diagnosing
  present participle

1. to determine the identity of (a disease, illness, etc.) by a medical examination.

   The doctor diagnosed the illness as influenza.

2. to ascertain the cause or nature of (a disorder, malfunction, problem, etc.) from the symptoms.

   The mechanic diagnosed the trouble that caused the engine knock.

3. to classify or determine on the basis of scientific examination.

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verb (used without object)

• diagnoses,
  present (3rd person singular)
• diagnosed,
  past participle,  past
• diagnosing
  present participle

1. to make a diagnosis.

diagnose British  

/ ˈdaɪəɡˌnəʊz /

verb

1. to determine or distinguish by diagnosis

2. (tr) to examine (a person or thing), as for a disease

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Other Word Forms

Derived Forms

• underdiagnose
  verb (used with object)
• diagnosable
  adjective
• undiagnosable
  adjective
• undiagnosed
  adjective
• well-diagnosed
  adjective

Inflected Forms

Participles

• diagnosing
  present
• diagnosed
  past

Conjugated Forms

Present

• diagnose
  simple
• diagnoses
  simple
• have diagnosed
  perfect
• has diagnosed
  perfect
• am diagnosing
  progressive
• are diagnosing
  progressive
• is diagnosing
  progressive
• have been diagnosing
  perfect progressive
• has been diagnosing
  perfect progressive

Past

• diagnosed
  simple
• had diagnosed
  perfect
• was diagnosing
  progressive
• were diagnosing
  progressive
• had been diagnosing
  perfect progressive

Future

• will diagnose
  simple
• will have diagnosed
  perfect
• will be diagnosing
  progressive
• will have been diagnosing
  perfect progressive

Etymology

Origin of diagnose

First recorded in 1860–65; back formation from diagnosis

Explanation

If you diagnose a disease, you recognize it by the signs and symptoms your patient shows. Your high temperature and the green crud you keep coughing up will allow your doctor to diagnose your bronchitis. The verb diagnose was first used in medicine, meaning "make a diagnosis," or identify a disease by observation of symptoms. Use it to describe the process of figuring it out. If you have bad gut pain, ask your doctor to diagnose your condition. You can also use diagnose for other problems, like if you diagnose poverty and malnutrition as the real causes of a student's terrible behavior, or diagnose the virus that caused your computer to crash.

Example Sentences

See Examples For:

diagnose diagnoses diagnosed diagnosing

Veterinarians continue extensive testing to diagnose famed Big Bear bald eagle Jackie, who remains anemic and sick with a still unknown condition.

From Los Angeles Times ● Aug. 8, 2026

In these cases, doctors may diagnose cancer largely by examining the appearance of cells in the bone marrow.

From Science Daily ● Aug. 1, 2026

Earlier this year, an international working group of canine-cognition experts published guidelines to diagnose and monitor cognitive dysfunction.

From The Wall Street Journal ● Jul. 30, 2026

I’m not saying to try to diagnose her from afar; in fact, a manager asking an employee about their health can be illegal in certain situations.

From MarketWatch ● Jul. 29, 2026

And thus anyone who does not diagnose the ills when they arise in a principality is not really wise, and this talent is given to few men.

From "The Prince" by Niccolò Machiavelli

People with dementia and Alzheimer’s diagnoses and their caregivers also must weigh other big milestones such as stopping driving, quitting a job or handing over management of household finances, Tan said.

From MarketWatch ● Aug. 17, 2026

Clinical geneticist Dr. Xiao P. Peng, who helped confirm Hinken’s family’s diagnoses, said the tools still make mistakes and are better at generating possible leads, translating complex medical jargon and compiling research than making diagnoses.

From The Wall Street Journal ● Aug. 15, 2026

Since the patients can’t tell you what’s wrong, it becomes a long process of ruling out diagnoses one by one, while providing supportive care and watching how the animal responds.

From Los Angeles Times ● Aug. 2, 2026

"Anecdotally, we're seeing a lot of people that are either threatening to bring claims or actually bringing claims, that don't have formal diagnoses," says Jo Moseley, a legal director at the firm.

From BBC ● Jul. 24, 2026

Gruby diagnoses a heart problem: that’s what is causing his great exhaustion.

From "Vincent and Theo: The Van Gogh Brothers" by Deborah Heiligman

His mother was diagnosed with cancer when he was 15, but it took another eight years for him to feel ready to turn some of those experiences into a script.

From BBC ● Aug. 15, 2026

The two chatbots got the diagnoses right in 13% and 10% of cases, respectively, compared with 5.6% of cases that doctors had diagnosed through a review of patients’ medical records.

From The Wall Street Journal ● Aug. 15, 2026

Others highlighted the vulnerability of a man who had been diagnosed with autism.

From Barron's ● Aug. 15, 2026

“A year and a half ago I was diagnosed with Stage 4 Breast Cancer, which has metastasized to my bones,” she wrote.

From Los Angeles Times ● Aug. 12, 2026

Then, at twenty-one, Grandma Jenny was diagnosed with cervical cancer and had a hysterectomy.

From "Three Little Words: A Memoir" by Ashley Rhodes-Courter

These particles may offer new biomarkers for diagnosing Alzheimer's disease and determining how far it has progressed.

From Science Daily ● Jul. 22, 2026

Even today, pathologists diagnosing disorders such as Alzheimer's disease typically inspect a handful of tissue samples from an organ containing some 86 billion neurons.

From BBC ● Jul. 13, 2026

Emergency room physicians were diagnosing diabetes in severely ill people who did not know they had the disease and treating life-threatening complications for those whose disease had long gone unmanaged.

From Los Angeles Times ● Jun. 14, 2026

Along with the $99 million settlement fund for plaintiffs, Illinois-based Deere agreed to expand access to its software for diagnosing problems and guiding fixes.

From The Wall Street Journal ● May 15, 2026

Doctors would do better in these cases if they knew less about their patients—if, that is, they had no idea whether the people they were diagnosing were white or black, male or female.

From "Blink" by Malcolm Gladwell

Related Words

• analyze
• determine
• investigate
• pinpoint
• pronounce
• recognize