diagnosis

noun

di·​ag·​no·​sis ˌdī-ig-ˈnō-səs 

-əg-

plural diagnoses ˌdī-ig-ˈnō-ˌsēz 

-əg-

1

a

: the art or act of identifying a disease from its signs and symptoms

b

: the decision reached by diagnosis

the doctor's diagnosis

2

a

: investigation or analysis of the cause or nature of a condition, situation, or problem

diagnosis of engine trouble

b

: a statement or conclusion from such an analysis

3

biology : a concise technical description of a taxon

Synonyms of diagnosis

• decision
• opinion
• verdict
• conclusion
• determination

Examples of diagnosis in a Sentence

The unusual combination of symptoms made accurate diagnosis difficult.

She is an expert in the diagnosis and treatment of eye diseases.

The diagnosis was a mild concussion.

His doctor made an initial diagnosis of pneumonia.

The committee published its diagnosis of the problems affecting urban schools.

Recent Examples on the Web

Why self-diagnosing can be misleading While social media can be a helpful starting point for recognizing symptoms, experts caution against self-diagnosis without a professional evaluation. — Rachel Hale, USA Today, 19 July 2026

Many of the physical aggressions KFF Health News identified in CMS inspection reports were perpetrated by residents with diagnoses of dementia, schizophrenia, or other cognitive disorders. — Jordan Rau, NPR, 19 July 2026

The lifetime risk of an Alzheimer’s diagnosis for an American 45-year-old is 1 in 5 for women and 1 in 10 for men. — Niya Doyle, PEOPLE, 19 July 2026

His defense attorney sought to reduce his $2 million bond, citing a recent debilitating disease diagnosis. — Amy McDaniel, Fort Worth Star-Telegram, 18 July 2026

Word History

Etymology

New Latin, from Greek diagnōsis, from diagignōskein to distinguish, from dia- + gignōskein to know — more at know

First Known Use

1634, in the meaning defined at sense 1a

Phrases Containing diagnosis

• diagnosis related group
• differential diagnosis

Rhymes for diagnosis

• cirrhosis
• fibrosis
• gliosis
• hypnosis
• ichthyosis
• ketosis
• kurtosis
• lordosis
• meiosis
• miosis
• mitosis
• mycosis

Kids Definition

diagnosis

noun

di·​ag·​no·​sis ˌdī-ig-ˈnō-səs 

plural diagnoses -ˈnō-ˌsēz 

1

a

: the art or act of identifying a disease from its signs and symptoms

b

: the decision reached by diagnosis

2

a

: a careful study of something especially to determine its nature or importance

b

: the conclusion reached after a study or examination

Medical Definition

diagnosis

noun

di·​ag·​no·​sis ˌdī-ig-ˈnō-səs, -əg- 

plural diagnoses -ˌsēz 

1

a

: the art or act of identifying a disease from its signs and symptoms

b

: the decision reached by diagnosis

a diagnosis of pneumonia

2

: a concise technical description of a taxon