diagnostic

1 of 2

adjective

di·​ag·​nos·​tic ˌdī-ig-ˈnä-stik How to pronounce diagnostic (audio)
-əg-
variants or less commonly diagnostical
1
a
: 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
diagnostically adverb

diagnostic

2 of 2

noun

1
: the art or practice of diagnosis
often used in plural
2
: a distinguishing mark
diagnostician 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
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Adjective
Hill and his colleagues acknowledge that their study has limitations, such as relying on diagnostic codes - which aren't necessarily equivalent to actual allergy rates. NPR, 21 Oct. 2025 The organization has a patient care center, with educational information, guidance on screening and diagnostic work, and ways to get emotional and financial support. Korin Miller, Flow Space, 20 Oct. 2025
Noun
This insurance provides coverage for illnesses, diagnostics, accidents, supportive care and more. Ryley Amond, CNBC, 12 Oct. 2025 The McMaster team’s broader research highlights how integrating biosensors, wearables, and AI could revolutionize diagnostics for women’s health — from reproductive conditions to cancer and osteoporosis. Neetika Walter, Interesting Engineering, 11 Oct. 2025 See All Example Sentences for diagnostic

Word History

First Known Use

Adjective

1625, in the meaning defined at sense 1a

Noun

1625, in the meaning defined at sense 1

Time Traveler
The first known use of diagnostic was in 1625

Cite this Entry

“Diagnostic.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/diagnostic. Accessed 22 Oct. 2025.

Kids Definition

diagnostic

adjective
di·​ag·​nos·​tic
ˌdī-ig-ˈnäs-tik
: of, relating to, or used in diagnosis
a diagnostic test for heart disease

Medical Definition

diagnostic

1 of 2 adjective
di·​ag·​nos·​tic -ˈnäs-tik How to pronounce diagnostic (audio)
variants also diagnostical
1
: of, relating to, or used in diagnosis
2
: using the methods of or yielding a diagnosis
a diagnostic service
diagnostic properties
diagnostically adverb

diagnostic

2 of 2 noun
: the art or practice of diagnosis
often used in plural

More from Merriam-Webster on diagnostic

Last Updated: - Updated example sentences
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