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

Children in these countries have less access to medical diagnostic and therapeutic interventions and are often diagnosed at later stages of illness with less access to curative therapy. — Emilee Flynn, The Conversation, 3 Nov. 2026

Her sisters said Taylor was diagnosed with Stage 3 cancer in 2022; after treatment brought remission, the disease returned as Stage 4. — Deborah Day, Los Angeles Times, 3 Nov. 2026

Dane died at 53 in February, less than one year after publicly announcing he had been diagnosed with amyotrophic lateral sclerosis (ALS). — Robert Powell, NBC news, 3 Nov. 2026

Nine months later, in late 2024, Dane was officially diagnosed with ALS. — Allison Degrushe, StyleCaster, 3 Nov. 2026

Word History

Etymology

back-formation from diagnosis

First Known Use

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

Rhymes for diagnose

• arkose
• engross
• faroese
• fructose
• fucose
• gatos
• glucose
• jocose
• morose
• plateaus
• spinose
• vadose

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-