di·​ag·​nos·​tic | \ ˌdī-ig-ˈnä-stik How to pronounce diagnostic (audio) , -əg- \
variants: or less commonly diagnostical \ ˌdī-​ig-​ˈnä-​sti-​kəl How to pronounce diagnostical (audio) , -​əg-​ \

Definition of diagnostic

 (Entry 1 of 2)

1a : of, relating to, or used in diagnosis a diagnostic tool
b : using the methods of or yielding a diagnosis diagnostic tests
2 : serving to distinguish or identify a diagnostic feature



Definition of diagnostic (Entry 2 of 2)

1 : the art or practice of diagnosis often used in plural
2 : a distinguishing mark

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Other Words from diagnostic


diagnostically \ ˌdī-​ig-​ˈnä-​sti-​k(ə-​)lē How to pronounce diagnostically (audio) , -​əg-​ \ adverb


diagnostician \ ˌdī-​ig-​(ˌ)nä-​ˈsti-​shən How to pronounce diagnostician (audio) , -​əg-​ \ noun

Examples of diagnostic in a Sentence

Adjective Ultrasound is now widely used as a diagnostic tool. One important diagnostic feature of this condition is a mild rash. Noun the thesis that moral decline is the infallible diagnostic of a decadent society
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Recent Examples on the Web: Adjective Laboratories have completed 494,337 diagnostic tests for COVID-19, 11.4% of which have come back positive. Brieanna J. Frank, The Arizona Republic, "Arizona coronavirus update: 70,051 confirmed cases, 1,579 known deaths as of Saturday," 28 June 2020 Pool testing relies on the same PCR technology as individual diagnostic tests. Andrew Joseph, STAT, "Safer reopening will require millions more Covid-19 tests per day. One solution: ‘pool testing’," 26 June 2020 As of May 12, Brazil had processed 337,595 diagnostic tests, according to Reuters. Cassidy Morrison, Washington Examiner, "Latin America is bearing the brunt of the coronavirus," 25 June 2020 In fact, there was one company, Seegene, who started working on it, on testing and diagnostic tests, before there had been a single case in South Korea when it was still considered to be a Chinese problem. Cnn Staff, CNN, "Lessons from South Korea: Dr. Sanjay Gupta's coronavirus podcast for June 24," 24 June 2020 Laboratories have completed 440,138 diagnostic tests for COVID-19, 10.5% of which have come back positive. Alison Steinbach, azcentral, "Arizona reports record number of new COVID-19 cases ahead of Trump visit," 23 June 2020 Other groups had organized similar events to develop diagnostic tests and help with the shortage of medical equipment, so why not do the same for research? Maimuna S. Majumder, Wired, "Coronavirus Researchers Are Dismantling Science’s Ivory Tower—One Study at a Time," 18 June 2020 Also Tuesday, Chicago officials said all six city-run testing sites will provide free diagnostic tests to anyone who has participated in a large gathering that put them at high risk of exposure, including recent protests over policing. USA TODAY, "Airport number war, Navajo lockdowns, petition rules: News from around our 50 states," 18 June 2020 Barnes is currently offering a combo deal: both antibody and diagnostic tests for $223. Laura Garcia, ExpressNews.com, "Drive-thru vehicle inspection shop has a new sideline: COVID-19 testing," 17 June 2020 Recent Examples on the Web: Noun Also advised is a consultation with your health-care provider about confirmation testing (a follow-up clinical diagnostic). Lisa Arbetter, Health.com, "Should You Try At-Home Genetic Testing? Here’s What You Need to Know," 4 June 2020 And the availability of having a diagnostic didn't change our ability to do the surveillance. Beth Mole, Ars Technica, "CDC says its testing fail didn’t hurt US response. Experts disagree," 29 May 2020 While antibody tests are easier to scale up than molecular diagnostics, which look for the presence of active virus in body fluids, the field has been plagued with accuracy challenges. James Paton, Bloomberg.com, "U.K. Regulator Urges Halt to Covid Finger-Prick Antibody Tests," 26 May 2020 The team has worked to understand how dangerous viruses jump from bats to humans, and to develop tools that could help researchers create diagnostics, treatments, and vaccines for human outbreaks. Meredith Wadman, Science | AAAS, "NIH’s axing of bat coronavirus grant a ‘horrible precedent’ and might break rules, critics say," 30 Apr. 2020 Von der Leyen said a pledge drive to fund the ACT Accelerator will take place on May 4 with a goal of raising $8 billion to ramp up the development of diagnostics, therapeutics and treatments. Deborah Netburn, Los Angeles Times, "$8-billion effort aims to speed development of coronavirus vaccines and treatments," 24 Apr. 2020 Shortly after the problems became apparent in early February, the Food and Drug Administration sent Timothy Stenzel, chief of in vitro diagnostics and radiological health, to the CDC to investigate what was going wrong. Beth Mole, Ars Technica, "CDC’s failed coronavirus tests were tainted with coronavirus, feds confirm," 20 Apr. 2020 The research will allow scientists to select the best animal on which to test diagnostics, vaccines and therapies to combat the virus. Laura Garcia, ExpressNews.com, "Texas Biomed raises $3.4M to work on COVID-19 vaccine," 3 Apr. 2020 Under that plan, all of the state's 373 nursing homes are receiving free tests and diagnostics. Mary Spicuzza, Milwaukee Journal Sentinel, "While concerns remain about reaching people of color, Wisconsin's free coronavirus testing is for everyone," 9 May 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'diagnostic.' 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 diagnostic


1625, in the meaning defined at sense 1a


1625, in the meaning defined at sense 1

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Time Traveler for diagnostic

Time Traveler

The first known use of diagnostic was in 1625

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Statistics for diagnostic

Last Updated

1 Jul 2020

Cite this Entry

“Diagnostic.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/diagnostic. Accessed 3 Jul. 2020.

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More Definitions for diagnostic


How to pronounce diagnostic (audio)

English Language Learners Definition of diagnostic

technical : of, relating to, or used in diagnosis : used to help identify a disease, illness, or problem

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