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

While that sounds obscure, the team’s work is foundational for advanced technological research in areas like computer chip manufacturing and medical diagnostic devices. —Alex Knapp, Forbes.com, 28 Mar. 2025

Conventional diagnostic tools – blood tests and polymerase chain reaction (PCR) analyses can take days to weeks. —New Atlas, 26 Mar. 2025

Noun

Goldman Sachs upgrades Danaher to buy from neutral Goldman Sachs upgraded the life sciences and diagnostics conglomerate and says the stock’s valuation is too attractive to ignore. —Michael Bloom, CNBC, 21 Mar. 2025

This means using advanced analytic insights to take a proactive approach to CX, where organizations use diagnostics, predictions, and prescriptions to manage the experiences of all customers rather than reacting to feedback from a small percentage who respond to surveys. —Forrester, Forbes, 21 Mar. 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