Updated on March 13, 2025
by PushtoLearn
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Plural of Diagnosis

The plural of diagnosis is diagnoses. The word diagnosis follows a special pluralization rule because it ends in -is. Similar to analysis and hypothesis, the -is changes to -es in the plural form.

TLDR

Singular and Plural Forms

Singular

Plural

diagnosis

diagnoses

The plural diagnoses is pronounced /ˌdaɪ.əɡˈnoʊ.siːz/ (dye-uh-NO-seeze).

Confusing Plural Forms Exercise

This exercise focuses on confusing plural forms, including Diagnosis.

Illustration of Plural of Diagnosis

How to Use "Diagnosis" in Sentences

Singular Example:

✅ The doctor gave her a diagnosis of diabetes.
✅ His diagnosis was confirmed after further tests.

Plural Example:

✅ The hospital handles many diagnoses every day.
✅ Several diagnoses were considered before deciding on treatment.

Common Mistakes

❌ "Diagnosises" (Incorrect) – The correct plural is diagnoses.
❌ "One diagnose" (Incorrect) – The singular is diagnosis, not diagnose (which is a verb).
❌ "A diagnoses" (Incorrect) – Diagnoses is plural, so it cannot take "a".

When to Use "Diagnosis"

  1. In Medicine – "His cancer diagnosis was early, which helped with treatment."

  2. In Psychology – "The psychologist provided a diagnosis of anxiety disorder."

  3. In Problem-Solving – "The mechanic’s diagnosis revealed a faulty engine."

FAQs

What is the plural form of diagnosis?

The plural of diagnosis is diagnoses.

How do you pronounce "diagnoses"?

It is pronounced /ˌdaɪ.əɡˈnoʊ.siːz/ (dye-uh-NO-seeze).

Do we say "this diagnosis is" or "these diagnosis are"?

  • Singular: "This diagnosis is correct."

  • Plural: "These diagnoses are serious."

What is the difference between "diagnosis" and "diagnose"?

  • Diagnosis = noun (e.g., "The doctor made a diagnosis.")

  • Diagnose = verb (e.g., "The doctor will diagnose the patient.")

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