Language questions often look simple at first glance.Then you pause.You think a little harder.Suddenly, grammar rules collide with history, habit, and real-world usage.
That’s exactly what happens when people ask what’s the plural of hippopotamus. You’ll hear hippopotamuses, hippopotami, and even hippos tossed around like they’re interchangeable. Some teachers insist on one form. Others shrug and accept all of them. Writers, meanwhile, just want to avoid sounding awkward.
This article clears up the confusion once and for all. You’ll learn which plural forms are correct, why the confusion exists, and which option works best in modern English. Along the way, you’ll see real dictionary evidence, usage data, and practical examples you can use right away.By the end, you’ll know exactly which plural to choose and why it matters.
Direct Answer: What Is the Plural of Hippopotamus?
The plural of hippopotamus is hippopotamuses.
The form hippopotami is also accepted, though it’s less preferred in modern English.
Why the Plural of Hippopotamus Confuses So Many People
English doesn’t play fair when it comes to plurals. Some words follow simple rules. Others feel like traps.
The confusion around the plural of hippopotamus comes from three main issues:
- English borrows words from many languages
- Some borrowed words keep foreign plural forms
- Many “-us” words look Latin even when they aren’t
People learn early on that words ending in -us often turn into -i. That works for cactus and fungus. It doesn’t always work elsewhere.
The problem is simple. Hippopotamus isn’t Latin. It only looks like it.
That misunderstanding creates years of grammar anxiety.
The Origin of the Word “Hippopotamus”
To understand the plural, you need to understand the word’s roots.
Hippopotamus comes from ancient Greek:
- hippos meaning horse
- potamos meaning river
Put together, the word literally means “river horse.”
Greek origin matters here. Latin nouns ending in -us often form plurals with -i. Greek nouns follow different rules. When English borrowed hippopotamus, it didn’t carry over a clean Greek plural system.
Instead, English did what it usually does. It adapted the word to fit English grammar.
That’s why hippopotamuses exists and works so well.
Is “Hippopotami” Grammatically Correct?
Yes, hippopotami is grammatically acceptable.
However, it’s based on analogy, not accuracy.
People see -us and assume a Latin plural. Over time, usage made hippopotami common enough to be recognized by dictionaries. Acceptance doesn’t always mean correctness in origin.
Think of it like this.
Language rewards what people actually say. Not what’s historically pure.
So while hippopotami isn’t wrong, it’s also not the most precise or modern option.
Why “Hippopotamuses” Is the Safest Choice
If clarity matters, hippopotamuses wins every time.
Here’s why writers and editors prefer it:
- It follows standard English plural rules
- It avoids false Latin assumptions
- It sounds natural to native speakers
- It appears most often in modern publications
Professional writing values readability. When readers don’t stop to question a word, the writing flows. Hippopotamuses do exactly that.
That’s why educators, journalists, and scientific communicators lean toward this form.
What Major Dictionaries Say About the Plural of Hippopotamus
Dictionaries don’t guess. They track real usage.
Here’s how major authorities treat the plural of hippopotamus:
| Dictionary | Accepted Plurals | Preferred Form |
| Merriam-Webster | hippopotamuses, hippopotami | hippopotamuses |
| Oxford English Dictionary | hippopotamuses, hippopotami | hippopotamuses |
| Cambridge Dictionary | hippopotamuses | hippopotamuses |
| Collins Dictionary | hippopotamuses, hippopotami | hippopotamuses |
Notice the pattern.
Every major dictionary favors hippopotamuses.
How Writers and Media Use the Plural in Real Life
Look beyond dictionaries and into real-world writing.
Modern news outlets, wildlife publications, and educational websites overwhelmingly use hippopotamuses. You’ll see it in:
- Zoo informational pages
- Wildlife conservation articles
- School textbooks
- Museum exhibits
Why? Because clarity beats cleverness.
Editors know that unfamiliar plural forms slow readers down. When communication matters, simplicity wins.
Is “Hippopotami” Ever the Better Choice?
Sometimes, yes.
Hippopotami may fit when:
- Writing creatively or stylistically
- Matching a specific academic tradition
- Using parallel forms with similar words
That said, it can sound forced if used just to appear sophisticated. Readers notice when a word feels out of place.
Good writing isn’t about showing off grammar knowledge. It’s about helping readers understand quickly.
What About “Hippos”?
In everyday conversation, hippos is the most common plural.
It’s informal, friendly, and widely accepted.
You’ll hear it in:
- Casual speech
- Children’s books
- Zoo signage
- Social media
There’s nothing wrong with using hippos when the tone allows it. Just avoid it in formal or academic writing where precision matters.
Singular and Plural Examples in Sentences
Seeing words in context makes everything clearer.
Singular usage
- A hippopotamus can weigh over 3,000 pounds.
Plural usage (preferred)
- Several hippopotamuses rested near the riverbank.
Plural usage (alternative)
- A group of hippopotami surfaced at dusk.
Informal usage
- The zoo’s hippos splashed loudly during feeding time.
Each form has its place. Context decides which one works best.
How Hippopotamus Compares to Similar Words
The confusion isn’t unique.
Many English words follow the same pattern:
| Word | Common Plural | Alternate Plural |
| Octopus | octopuses | octopi |
| Cactus | cactuses | cacti |
| Fungus | funguses | fungi |
| Hippopotamus | hippopotamuses | hippopotami |
English favors -es endings over time. It’s simpler. It’s consistent. It works.
Common Mistakes People Make With Hippopotamus Plurals
Some errors show up again and again.
- Assuming every -us word becomes -i
- Using hippopotami to sound more educated
- Mixing plural forms in the same paragraph
- Ignoring audience expectations
Clear writing respects the reader. When in doubt, choose the form that feels natural.
Final Verdict: Which Plural Should You Use?
If you want one answer you can rely on, here it is:
Use hippopotamuses.
It’s grammatically correct.
It’s dictionary-approved.
It’s widely used.
It won’t distract your readers.
Hippopotami isn’t wrong, but it’s optional.
Hippos works when the tone is casual.
Choose the form that matches your audience and purpose.
FAQs
Is “hippopotami” incorrect?
No. It’s accepted, but not preferred in modern English.
Why doesn’t hippopotamus follow Greek plural rules?
English adapts borrowed words instead of preserving original grammar systems.
What plural do teachers recommend?
Most educators recommend hippopotamuses for clarity.
Which plural appears most in books and articles?
Usage data shows hippopotamuses appears far more often in modern writing.
Conclusion
The plural of hippopotamus is a perfect example of how English blends history, usage, and practicality. While both hippopotamuses and hippopotami are technically correct, modern English and dictionary authorities overwhelmingly favor hippopotamuses. It’s clear, readable, and widely recognized, making it the safest choice for professional writing, academic work, and general communication.
At the same time, hippopotami can be used in creative or formal contexts where a stylistic touch is desired, and hippos works perfectly in casual conversation or informal writing. Understanding the origins of the word—from Greek roots meaning “river horse”—helps explain why pluralization can feel tricky, but also why clarity should guide your choice
Read More:Heyday or Hayday: What’s the Right Word to Use? (Complete Expert Guide)
