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 Experts say this is unhelpful and potentially misleading, because antibody tests aren't used to diagnose current infections or determine whether someone is potentially contagious. Ivana Kottasová, CNN, "What you need to know about coronavirus on Saturday, May 23," 23 May 2020 These tests are typically used to diagnose a COVID-19 infection. Beth Mole, Ars Technica, "Recovered COVID-19 patients test positive but not infectious, data finds," 19 May 2020 Two more children in the state have been diagnosed with a potentially fatal inflammatory disease linked to the virus, Beshear said. Jonathan Bullington, The Courier-Journal, "Coronavirus roundup: Beshear eyes contact tracing amid 'big week' for Kentucky's reopening," 18 May 2020 So far, six members of the sumo association have been diagnosed with the virus, per CNN. Eric Todisco, PEOPLE.com, "Sumo Wrestler Shobushi, 28, Dies After Coronavirus Diagnosis," 13 May 2020 Those tests more closely resemble the ones used to diagnose the virus in the United States, which are done in laboratories on high-capacity machines that can process hundreds of samples at a time. Michael D. Shear, New York Times, "White House Races to Contain Virus in Its Ranks: ‘It Is Scary to Go to Work’," 10 May 2020 Last week, Abbott’s m2000 RealTime system got U.S. Food and Drug Administration approval for use in hospitals and molecular laboratories to diagnose the infection. Michelle Fay Cortez, Bloomberg.com, "Abbott Surges After Unveiling Five-Minute Coronavirus Test," 10 May 2020 Share this - Erika Edwards 10h ago / 9:49 AM PDT FDA clears way for first mail-in COVID-19 spit test The Food and Drug Administration has authorized the first test that uses saliva, rather than an uncomfortable nasal swab, to diagnose COVID-19. NBC News, "Photo: Social distancing at Lebanese mosque," 8 May 2020 Antigen tests used to diagnose viral infections such as the flu are even less sensitive, often reporting a negative result when the virus is actually present. Jim Daley, Scientific American, "‘Breakthrough’ COVID-19 Tests Are Currently Cheap, Fast—and Not Very Accurate," 7 May 2020

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 1841, in the meaning defined at transitive sense 1a

History and Etymology for diagnose

back-formation from diagnosis

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Time Traveler for diagnose

Time Traveler

The first known use of diagnose was circa 1841

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Statistics for diagnose

Last Updated

29 May 2020

Cite this Entry

“Diagnose.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/diagnose. Accessed 30 May. 2020.

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More Definitions for diagnose


How to pronounce diagnose (audio) How to pronounce diagnose (audio)

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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