The plural of prognosis is prognoses. This word follows the Greek plural rule where the singular ending -sis changes to -ses. So, one prognosis, two prognoses. This is the only correct plural form in standard medical and general English.
Quick Answer
Singular: prognosis
Plural: prognoses
Pronunciation: prog-NOH-seez (singular) / prog-NOH-seez (plural — same spelling but pronounced with a longer eez sound at the end)
Do not write prognosises or prognosi. Those are incorrect.
Why It Is Prognoses
Many medical terms come from Greek. Words ending in -sis (like diagnosis, analysis, thesis) form their plural by changing -sis to -ses. This is a fixed rule, not a choice. Prognosis works the same way.
If you are writing a medical report, an email to a colleague, or a study note, always use prognoses for more than one prognosis. In everyday conversation, the same rule applies, though people sometimes say prognoses less often because they rarely talk about multiple prognoses at once.
Comparison Table: Singular vs. Plural
| Form | Example | Context |
|---|---|---|
| Singular: prognosis | The doctor gave a cautious prognosis. | One patient, one condition |
| Plural: prognoses | The team reviewed three different prognoses. | Multiple patients or scenarios |
| Incorrect: prognosises | We compared the prognosises. (wrong) | Do not use |
| Incorrect: prognosi | All prognosi were similar. (wrong) | Do not use |
Natural Examples
Here are examples you might hear or write in real situations. Pay attention to the context and tone.
Formal / Medical Report
- The prognoses for patients in the trial varied significantly.
- Each case file contains a separate prognosis; we will compare all prognoses at the meeting.
Email to a Colleague
- Could you send me the prognoses for the three new admissions?
- I have updated the prognosis for Room 204, but the other prognoses remain unchanged.
Everyday Conversation
- The vet gave two different prognoses for the two dogs.
- I asked about my grandmother’s prognosis, but the doctor mentioned several possible prognoses depending on treatment.
In conversation, people sometimes say prognosis even when referring to multiple cases, but careful speakers and writers use prognoses for clarity.
Common Mistakes
Even native speakers make errors with this word. Here are the most frequent ones.
- Mistake: Writing prognosises.
Correct: Prognoses. Adding -es to the end is a common overcorrection. - Mistake: Using prognosis as both singular and plural.
Correct: Use prognoses for plural. Saying “several prognosis” is ungrammatical. - Mistake: Confusing prognosis with diagnosis.
Note: A diagnosis identifies a condition; a prognosis predicts the outcome. Both form plurals the same way: diagnoses and prognoses. - Mistake: Mispronouncing the plural. Some people say prog-NOH-sis for both. The plural should sound like prog-NOH-seez (rhymes with seas).
Better Alternatives and When to Use Them
Sometimes you may want to avoid the word prognoses if you think your reader might not be familiar with it. Here are alternatives and their appropriate contexts.
- Outlooks — Use in informal conversation or patient-friendly communication. Example: “The outlooks for both patients are good.”
- Predictions — Use in general discussion, not in formal medical writing. Example: “The predictions from the two specialists differed.”
- Expected outcomes — Use in patient education materials or emails to non-medical staff. Example: “We discussed the expected outcomes for each treatment plan.”
- Forecasts — Use very informally, but avoid in clinical notes. Example: “The forecasts for recovery were optimistic.”
When to use prognoses: In medical charts, research papers, formal reports, and any professional healthcare setting. Use the alternatives when speaking with patients or writing for a general audience.
Mini Practice: 4 Questions
Test yourself. Choose the correct form for each sentence.
- The doctor gave a __________ for each of the five patients.
a) prognosis b) prognoses c) prognosises - We need to compare the __________ from the two clinics.
a) prognosis b) prognoses c) prognosi - Her __________ was better than expected.
a) prognosis b) prognoses c) prognosises - All __________ were recorded in the system.
a) prognosis b) prognoses c) prognosises
Answers
- b) prognoses (five patients, so plural)
- b) prognoses (two clinics, so plural)
- a) prognosis (her, singular)
- b) prognoses (all, plural)
Frequently Asked Questions
1. Is prognoses the only correct plural?
Yes. In standard English, both medical and general, the only accepted plural is prognoses. You may see prognosises in very informal writing, but it is considered a mistake.
2. Can I use prognosis as a plural in casual speech?
Some people do, but it is not grammatically correct. If you want to sound careful and clear, use prognoses even in conversation. If you feel the word sounds too formal, use an alternative like outlooks.
3. How do I pronounce prognoses?
Say it as prog-NOH-seez. The last syllable sounds like seas or please. The singular prognosis ends with a shorter sis sound.
4. Does the same rule apply to diagnosis and analysis?
Yes. Diagnosis becomes diagnoses, and analysis becomes analyses. All Greek -sis words follow this pattern. Learning one helps you remember the others.
For more help with medical plurals, visit our Common Plural Forms section or check the FAQ page for quick answers. If you have a specific question, feel free to contact us. Our editorial policy explains how we ensure accuracy in every guide.
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