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

Providing Rapid Diagnosis Of Common Conditions Mobile devices are evolving into personal diagnostic hubs. —Expert Panel®, Forbes.com, 18 Apr. 2025

That is in keeping with the position of experts, who have maintained for years that increases in autism cases are a mere function of better screening and a widening of the diagnostic criteria of what constitutes the condition. —Jeffrey Kluger, Time, 18 Apr. 2025

Noun

The company partnered with Think PLC to implement Siemens drives and an automation portal for real-time monitoring, diagnostics, and control. —Steve McDowell, Forbes.com, 17 Apr. 2025

Segment sales: Nutrition beat, diagnostics missed, pharmaceuticals beat, and medical devices beat. —Jim Cramer, CNBC, 16 Apr. 2025

Word History

First Known Use

Adjective

1625, in the meaning defined at sense 1a

Noun

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