di·​ag·​nose | \ ˈdī-ig-ˌnōs How to pronounce diagnose (audio) , -ˌnōz, ˌdī-ig-ˈnōs How to pronounce diagnose (audio) , -ˈnōz, -əg-\
diagnosed; diagnosing

Definition of diagnose

transitive verb

1a : to recognize (something, such as a disease) by signs and symptoms The other method of diagnosing gallstones is through an ultrasound examination, which has the advantages of being simple, safe and quick.— G. Timothy Johnson Pulmonary embolus was diagnosed in two of the actively treated patients …— Richard D. Sautter et al.
b : to recognize a disease or condition in The physicist and cosmologist was diagnosed with Lou Gehrig's disease when he was a 21-year-old student at Cambridge University.— Maria Cheng
2 : to analyze the cause or nature of The mechanic diagnosed the problem with the engine.

intransitive verb

: to identify a disease from its signs and symptoms : to make a diagnosis

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Other Words from diagnose

diagnosable or diagnoseable \ ˌdī-​ig-​ˈnō-​sə-​bəl How to pronounce diagnoseable (audio) , -​əg-​ , -​zə-​ \ adjective

Examples of diagnose in a Sentence

The test is used to help in diagnosing heart disease. Thousands of new cases have been diagnosed in the past year. The doctor was unable to diagnose the skin condition. a new doctor with little experience diagnosing patients The mechanic was unable to diagnose the problem.
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Recent Examples on the Web

In a sweet show of support, all of Foster’s kids were on hand for their father’s special day, including eldest daughter Amy, who recently revealed she was diagnosed with breast cancer and will undergo a double mastectomy operation. Morgan M. Evans, PEOPLE.com, "Katharine McPhee Jokes About David Foster’s Instagram Husband Skills During Italian Honeymoon," 8 July 2019 At the time, Wilson was one of only a handful of people in the world to ever be diagnosed with a Bourbon virus infection, and the second to succumb to the mysterious microbe since it was discovered in 2014. Megan Molteni, WIRED, "The Meat-Allergy Tick Also Carries a Mystery Killer Virus," 8 July 2019 The Cobra,'' as he was known in his playing days, had two knee surgeries and was diagnosed in 2012 with Parkinson’s Disease, which attacks the brain nerve cells and affects movement. Branson Wright, cleveland.com, "40 years after historic All-Star Game, Dave Parker battles Parkinson’s, helps at Reds Youth Academy," 7 July 2019 Cleveland Indians starting pitcher Carlos Carrasco has been diagnosed with leukemia, Carrasco announced. Alaa Abdeldaiem, SI.com, "Cleveland Indians Pitcher Carlos Carrasco Diagnosed With Leukemia," 6 July 2019 Her mom Before Schneider was born, her mom, Jill Kumlien, was diagnosed with MS. Hannah Kirby, Milwaukee Journal Sentinel, "She ran across the US for her mom with multiple sclerosis. Now, she puts on a fundraising relay for MS.," 5 July 2019 The team also found that individuals with CTE were diagnosed with traumatic brain injuries no more often than people whose brains lacked CTE. Sabine Galvis, Science | AAAS, "Even if you don’t play contact sports, you could develop signs of traumatic brain injury," 3 July 2019 She was rushed to the emergency room by ambulance and was diagnosed with necrotizing fasciitis, a rare but deadly bacterial infection that kills the body's soft tissue. CBS News, "Maryland boy infected with flesh-eating bacteria, mother says," 3 July 2019 Peninsula Regional Health System physicians diagnosed the boy with Vibrio, Brittany Carey shared in her Facebook post on Saturday. Susan Scutti, CNN, "Maryland boy victim of flesh-eating bacteria after a swim off the coast of Maryland," 3 July 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'diagnose.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of diagnose

circa 1859, in the meaning defined at transitive sense 1

History and Etymology for diagnose

back-formation from diagnosis

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Statistics for diagnose

Last Updated

11 Jul 2019

Look-up Popularity

Time Traveler for diagnose

The first known use of diagnose was circa 1859

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More Definitions for diagnose



English Language Learners Definition of diagnose

: to recognize (a disease, illness, etc.) by examining someone
: to recognize a disease, illness, etc., in (someone)
: to find the cause of (a problem)


di·​ag·​nose | \ ˈdī-əg-ˌnōs How to pronounce diagnose (audio) \
diagnosed; diagnosing

Kids Definition of diagnose

: to recognize (as a disease) by signs and symptoms The test is used for diagnosing strep throat.


di·​ag·​nose | \ ˈdī-ig-ˌnōs How to pronounce diagnose (audio) , -ˌnōz How to pronounce diagnose (audio) , ˌdī-ig-ˈ, -əg-\
diagnosed; diagnosing

Medical Definition of diagnose

transitive verb

1 : to recognize (as a disease) by signs and symptoms
2 : to diagnose a disease or condition in diagnosed the patient

Other Words from diagnose

diagnosable also diagnoseable \ ˌdī-​ig-​ˈnō-​sə-​bəl, -​əg-​, -​zə-​ How to pronounce diagnoseable (audio) \ adjective

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More from Merriam-Webster on diagnose

Rhyming Dictionary: Words that rhyme with diagnose

Spanish Central: Translation of diagnose

Nglish: Translation of diagnose for Spanish Speakers

Britannica English: Translation of diagnose for Arabic Speakers

Comments on diagnose

What made you want to look up diagnose? Please tell us where you read or heard it (including the quote, if possible).


to form ideas or theories about something

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