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

Many of the condition’s early signs, such as depression or impulsivity, can stem from other factors, and some experts worry about making premature diagnoses. — Alexandra Pattillo, Scientific American, 23 Sep. 2026

But in subsequent updates to its NHS study, Grail clarified that Stage IV cancer diagnoses (not combined with Stage III) decreased over its three-year study period, suggesting tests may have shifted cancer diagnosis to earlier stages. — Yuki Noguchi, NPR, 23 Sep. 2026

His book is filled with detailed accounts of patients who responded in different ways to their diagnosis. — Steve Lopez, Los Angeles Times, 23 Sep. 2026

Joseph Wayne Singleton, a 45-year-old musician from Opelousas, Louisiana, shared how a routine physical led to an early diagnosis that saved his life. — Angelica Stabile, FOXNews.com, 23 Sep. 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