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

AI models are helping diagnose cancer at earlier stages and develop cures.

From The Wall Street Journal ● Aug. 31, 2026

Grace's GP did not diagnose her condition and nor did the first consultant she saw privately.

From BBC ● Aug. 23, 2026

New leadership has recently made an effort to diagnose the chain’s problems — cutting the dividend and pulling the company’s full-year forecast in an effort to drive a bigger turnaround effort.

From MarketWatch ● Aug. 8, 2026

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

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

Such mistakes include missing the signs of acute deterioration in patients, failing to order the necessary tests and scans and making incorrect diagnoses.

From BBC ● Sep. 8, 2026

Lung cancer continues to rank first globally for both new diagnoses and cancer deaths, with tobacco remaining the main driver of the disease.

From Science Daily ● Sep. 7, 2026

The girls in Kenworthy’s study already had autism diagnoses.

From Los Angeles Times ● Aug. 26, 2026

That’s due in part to “coding intensity,” meaning the inclusion of more diagnoses for Medicare Advantage enrollees.

From MarketWatch ● Aug. 24, 2026

He still spent most of his time in Haiti, but as an attending specialist on the Brigham’s senior staff, he was sought after frequently for his diagnoses of ID—infectious diseases.

From "Mountains Beyond Mountains" by Tracy Kidder and Michael French

Bonino was diagnosed in 2015 with pulmonary microcytoma -- a particularly aggressive lung cancer -- receiving the all clear in 2023.

From Barron's ● Sep. 11, 2026

A Department of Health and Social Care spokesperson says the National Cancer Plan "will help more people get diagnosed earlier and begin treatment sooner".

From BBC ● Sep. 10, 2026

He was eventually diagnosed with an annular tear and given two possible recovery timelines.

From Los Angeles Times ● Sep. 9, 2026

Colorectal cancer incidence among Americans under age 49 is increasing by about 3 percent per year, and about 83,000 Americans between ages 20 and 39 are diagnosed with cancer annually.

From Slate ● Sep. 9, 2026

By morning, the toe had turned purple and he diagnosed a fracture.

From "Mountains Beyond Mountains" by Tracy Kidder and Michael French

I’m also a physician, trained in a profession that asks us to take action by identifying risk factors, diagnosing diseases, and intervening whenever possible.

From Slate ● Aug. 29, 2026

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

From Science Daily ● Jul. 22, 2026

Sarah Hendrickx had spent years diagnosing autism in boys and men yet says she "failed miserably to apply it to myself".

From BBC ● Jul. 7, 2026

An Alzheimer’s specialist says science will continue to make great leaps in diagnosing and treating Alzheimer’s.

From The Wall Street Journal ● Jun. 20, 2026

This is why we keep statistics in sports, and why it makes sense to do a computer analysis of all the factors that go into diagnosing heart attacks.

From "Blink" by Malcolm Gladwell

Related Words

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