What’s the plural of “diagnosis”?
A diagnosis is the “recognition of a disease from its symptoms” or the “discovery or identification of the cause of an illness or a problem.” Doctors and other professionals reach a diagnosis by observing the signs and symptoms of a disease, condition, or injury.
- Diagnosis (pronounced dye-ahg-no-sis) is singular.
- Diagnoses (pronounced dye-ahg-no-seez) is plural.
As a noun, diagnosis is irregular (it doesn’t add “es”, but modifies its singular suffix by swapping the “-is” with “-es” to switch to plural).
| Singular | Plural |
|---|---|
| crisis | crises |
| diagnosis | diagnoses |
| oasis | oases |
| synopsis | synopses |
The plural of “diagnosis”: associate it with other words ending in “-sis” that change to “-ses” for the plural, like “analysis” becomes “analyses.”
Sentence examples: diagnosis & diagnoses
| Noun: diagnosis | Example sentences |
|---|---|
| diagnosis |
The doctor's diagnosis confirmed a mild concussion after the fall. Her final diagnosis came after a series of imaging tests. Receiving an early diagnosis improved his chances of recovery. The specialist offered a second opinion on the tentative diagnosis. |
| diagnoses (plural) |
The patient's prior diagnoses were all noted in his medical record. Multiple diagnoses made the treatment plan more complex. Clinic staff reviewed the team's earlier diagnoses during the case conference. |
Quotes from the media & literature, with diagnosis
[Swindlers] seem to possess, in an extraordinarily high degree, the power of diagnosis,—of telling what are the weak spots in the mind of the ordinary man.
The ‘Genera Piscium’ contains well-defined diagnoses of 45 genera.
The crows can form a pretty correct diagnosis upon the case of a sick camel.
Then came the diagnosis—to wit a severe contusion and strain of right knee.
Synonyms & nearby words
| Synonym | Nearby word |
|---|---|
| decision | finding |
| conclusion | result |
| judgment | opinion |
| resolution | assessment |
| determination | evaluation |
| verdict | report |
Origin of the word diagnosis
Diagnosis comes from Greek διάγνωσις (diágnōsis), meaning “a distinguishing, discernment, decision,” from διαγιγνώσκειν (diagignóskein), “to distinguish, discern.”
Worksheet: Greek nouns
FAQs
Q: What is the plural of “diagnosis”?
Q: How is “diagnoses” (plural) pronounced?
Q: Why is “diagnoses” spelled differently?
Q: How do I use diagnosis vs diagnoses?
Q: Are other words like diagnosis pluralized?
Sources
- Norgate, G. Le G., and Sayoni Basu. "Wilson, Henry Schütz (1824–1902), literary scholar." Oxford Dictionary of National Biography. September 23, 2004. Oxford University Press. Date of access 7 Sep. 2025,
Yash, D. "How to Use Diagnosis Plural (Diagnoses, Diagnoseses?)." Grammarflex, Sep 7, 2025, https://grammarflex.com/diagnosis-plural/.
