diagnose

verb

di·​ag·​nose ˈdī-ig-ˌnōs 

-ˌnōz, 

ˌdī-ig-ˈnōs 

-ˈnōz, 

-əg-

diagnosed; diagnosing

transitive verb

1

a

: to recognize (something, such as a disease) by signs and symptoms

The other method of diagnosing gallstones is through an ultrasound examination, which has the advantages of being simple, safe and quick.

—G. Timothy Johnson

Pulmonary embolus was diagnosed in two of the actively treated patients …

—Richard D. Sautter et al.

b

: to recognize a disease or condition in

The physicist and cosmologist was diagnosed with Lou Gehrig's disease when he was a 21-year-old student at Cambridge University.

—Maria Cheng

2

: to analyze the cause or nature of

The mechanic diagnosed the problem with the engine.

intransitive verb

: to identify a disease from its signs and symptoms : to make a diagnosis

diagnosable adjective

or diagnoseable

ˌdī-ig-ˈnō-sə-bəl 

-əg-, 

-zə-

Examples of diagnose in a Sentence

The test is used to help in diagnosing heart disease.

Thousands of new cases have been diagnosed in the past year.

The doctor was unable to diagnose the skin condition.

a new doctor with little experience diagnosing patients

The mechanic was unable to diagnose the problem.

Recent Examples on the Web

Dench, who is now healthy after being diagnosed with breast cancer in 2024, wasn’t well enough to travel for Thanksgiving last year, so the pair opted for a joint Instagram Live. —Melina Khan, USA Today, 22 Nov. 2025

American Cancer Society releases annual report Tatiana Schlossberg, the daughter of Caroline Kennedy, revealed in an emotional essay published Saturday that she has been diagnosed with terminal cancer. —Ivan Pereira, ABC News, 22 Nov. 2025

Bruce retired from acting in 2022, after he was diagnosed with aphasia that has since progressed to frontotemporal dementia (FTD). —Nicholas Rice, PEOPLE, 22 Nov. 2025

Bruce Willis and Demi Moore's daughter Rumer Willis shared an update on the health of her father who is diagnosed with frontotemporal dementia (FTD). —Megan Cartwright, MSNBC Newsweek, 21 Nov. 2025

Word History

Etymology

back-formation from diagnosis

First Known Use

circa 1841, in the meaning defined at transitive sense 1a

Rhymes for diagnose

• adios
• adipose
• amylose
• bellicose
• cellulose
• centavos
• comatose
• grandiose
• granulose
• levulose
• overdose
• ribulose

Kids Definition

diagnose

verb

di·​ag·​nose ˈdī-ig-ˌnōs  -ˌnōz 

ˌdī-ig-ˈnōs, 

-ˈnōz

diagnosed; diagnosing

: to recognize by signs and symptoms : make a diagnosis

diagnose a disease

diagnose a play in football

Medical Definition

diagnose

verb

di·​ag·​nose ˈdī-ig-ˌnōs  -ˌnōz 

ˌdī-ig-ˈ, 

-əg-

diagnosed; diagnosing

transitive verb

1

: to recognize (as a disease) by signs and symptoms

2

: to diagnose a disease or condition in

diagnosed the patient

intransitive verb

: to make a diagnosis

diagnosable adjective

also diagnoseable

ˌdī-ig-ˈnō-sə-bəl, -əg-, -zə-