diagnostic

1 of 2

adjective

di·​ag·​nos·​tic ˌdī-ig-ˈnä-stik 

-əg-

variants or less commonly diagnostical

ˌdī-ig-ˈnä-sti-kəl 

-əg-

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

ˌdī-ig-ˈnä-sti-k(ə-)lē 

-əg-

adverb

diagnostic

2 of 2

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

Adjective

• characteristic
• classic
• discriminating
• distinct
• distinctive
• distinguishing
• identifying
• individual
• peculiar
• proper
• symptomatic
• typical

Noun

• affection
• attribute
• attribution
• character
• characteristic
• criterion
• differentia
• feature
• fingerprint
• hallmark
• mark
• marker
• note
• particularity
• peculiarity
• point
• property
• quality
• specific
• stamp
• touch
• trait

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

Adjective

Without it, there is no coverage for doctors’ visits, diagnostic tests, or outpatient procedures, services and some medications. —Diane Omdahl, Forbes, 21 Jan. 2025

In health care, that value seems clear—for example, additional AI diagnostic tools are expected to gain FDA approval, and AI may also prove useful in discovering and monitoring the long-term impact of various drugs. —Tharin Pillay, TIME, 16 Jan. 2025

Noun

Due to a surprise medical diagnostic from the top-10 selection, Darnold was flung into the starting role just weeks before the start of the season. —Tyler Small, Forbes, 15 Jan. 2025

Zoom out: Analysts foresee the broader diagnostics industry going gangbusters in the next decade, Axios Pro's Erin Brodwin wrote last month. —Maya Goldman, Axios, 9 Jan. 2025

Word History

First Known Use

Adjective

1625, in the meaning defined at sense 1a

Noun

1625, in the meaning defined at sense 1

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