diagnostic

noun

1

: the art or practice of diagnosis

—often used in plural

2

: a distinguishing mark

diagnostician

ˌdī-ig-(ˌ)nä-ˈsti-shən 

-əg-

noun

Synonyms of diagnostic

• characteristic
• feature
• quality
• trait
• attribute
• attribution
• criterion

Examples of diagnostic in a Sentence

the thesis that moral decline is the infallible diagnostic of a decadent society

Recent Examples on the Web

There were machines that assessed my body from the outside and from within; tests that looked at composition, function and performance; cognitive diagnostics that felt oddly enjoyable; and strength assessments that were, frankly, less charming. —Rachel Ingram, Robb Report, 7 June 2026

To safeguard users every mile of the trip, the trailer has 360-degree monitoring, automotive-grade brakes (including ABS, EBD, and ESC), smoke and gas sensors, and complete vehicle diagnostics. —Connie Etemadi, USA Today, 4 June 2026

Doctors could perform advanced medical diagnostics in remote villages using handheld tools. —Mrigakshi Dixit, Interesting Engineering, 3 June 2026

Andersen was involved in developing diagnostics and conducted genomic sequencing of Ebola virus genomes during past outbreaks to learn how the virus was evolving and spreading. —Eric Berger, ArsTechnica, 29 May 2026

Word History

First Known Use

1625, in the meaning defined at sense 1

Rhymes for diagnostic

• acrostic
• agnostic
• encaustic
• prognostic
• caustic
• gnostic

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 

variants also diagnostical

-ti-kəl 

1

: of, relating to, or used in diagnosis

2

: using the methods of or yielding a diagnosis

a diagnostic service

diagnostic properties

diagnostically

-ti-k(ə-)lē 

adverb

diagnostic

2 of 2 noun

: the art or practice of diagnosis

—often used in plural