What is the correct plural of “hippopotamus”? Is it hippopotamuses or hippopotami? Many English learners and native speakers search for this question because both forms appear online, in books, and even in news articles.

The confusion comes from the history of the word. “Hippopotamus” has roots in ancient Greek, but English grammar has changed the way many old words become plural. Some people prefer the classic form hippopotami, while others use the more modern and common hippopotamuses.

This article gives a quick answer first, then explains the origin, spelling rules, usage differences, and common mistakes. You will also see real-life examples, comparison tables, and FAQs that help you understand which plural form works best in formal writing, casual speech, school assignments, and professional communication.

If you have ever wondered which version sounds correct, this guide will solve the confusion in simple English.

---

Plural of Hippopotamus – Quick Answer

The plural of hippopotamus can be:

• Hippopotamuses (most common in modern English)
• Hippopotami (less common but still accepted)

Examples

• The zoo has three hippopotamuses.
• Several hippopotami were resting in the river.

Both forms are correct, but hippopotamuses is more common in everyday English.

---

The Origin of Plural of Hippopotamus

The word hippopotamus comes from ancient Greek:

• Hippos = horse
• Potamos = river

Together, the word means “river horse.”

The original Greek plural would not actually be hippopotami. That ending became popular because many English speakers copied Latin-style plural rules used in words like:

• cactus → cacti
• alumnus → alumni

Over time, English created its own regular plural form by simply adding -es:

• hippopotamus → hippopotamuses

This is why both forms exist today.

Why the Spelling Differences Exist

English borrows words from many languages. Some keep their old plural endings, while others follow normal English grammar rules.

That is why English accepts:

Singular	Traditional Plural	Modern English Plural
Hippopotamus	Hippopotami	Hippopotamuses
Cactus	Cacti	Cactuses
Octopus	Octopi	Octopuses

---

British English vs American English Spelling

Both British and American English accept hippopotamuses and hippopotami. However, usage style can differ slightly.

• American English usually prefers hippopotamuses.
• British English also commonly uses hippopotamuses, but traditional forms sometimes appear in academic or literary writing.

Comparison Table

Feature	American English	British English
Most common form	Hippopotamuses	Hippopotamuses
Traditional form	Hippopotami	Hippopotami
Formal writing	Mostly regular plurals	Mix of both forms
Everyday speech	Hippopotamuses	Hippopotamuses

Example Sentences

Style	Sentence
American English	The hippopotamuses were fed at noon.
British English	The hippopotami rested near the riverbank.

---

Which Spelling Should You Use?

The best choice depends on your audience.

Use “Hippopotamuses” When:

• Writing for general readers
• Creating school assignments
• Writing blog posts
• Using simple modern English
• Writing for international audiences

Use “Hippopotami” When:

• Writing in a classic or literary style
• Using formal academic language
• Referring to traditional plural forms

Best Advice

If you are unsure, choose hippopotamuses. It is clearer and more widely accepted today.

---

Common Mistakes with Plural of Hippopotamus

Many people make small grammar mistakes with this word.

Incorrect: Hippopotamuses

❌ There are many hippopotamuses in the lake.

Correct:

✅ There are many hippopotamuses in the lake.

---

Incorrect: Hippopotamusses

❌ The hippopotamusses are sleeping.

Correct:

✅ The hippopotamuses are sleeping.

---

Incorrect Singular and Plural Mix

❌ One hippopotami is swimming.

Correct:

✅ One hippopotamus is swimming.

---

Quick Correction Table

Wrong Form	Correct Form
Hippopotamuses	Hippopotamuses
Hippopotamusses	Hippopotamuses
One hippopotami	One hippopotamus

---

Plural of Hippopotamus in Everyday Examples

Here are examples from daily communication.

In Emails

• The wildlife park recently added two new hippopotamuses.

In News Writing

• Several hippopotamuses escaped during the flood.

On Social Media

• Look at these cute baby hippopotamuses!

In Formal Writing

• The behavior of the hippopotami was carefully observed.

In Classroom Writing

• We learned that hippopotamuses spend much of their time in water.

---

Plural of Hippopotamus – Google Trends & Usage Data

Search interest for “plural of hippopotamus” is common in countries where English learners study grammar heavily.

Popular Regions

• United States
• United Kingdom
• India
• Canada
• Australia

Most Commonly Used Form

Online usage shows that hippopotamuses appears more often in:

• Educational websites
• News articles
• Children’s books
• Modern dictionaries

Meanwhile, hippopotami appears more in:

• Academic writing
• Literature
• Classical language discussions

Usage Comparison Table

Variation	Popularity	Common Context
Hippopotamuses	Very high	Everyday English
Hippopotami	Medium	Formal or literary English
Hippopotamuses	Incorrect	Grammar mistake

---

Comparison Table of Keyword Variations

Singular	Correct Plural	Alternative Plural	Incorrect Form
Hippopotamus	Hippopotamuses	Hippopotami	Hippopotamuses

---

FAQs About Plural of Hippopotamus

What is the correct plural of hippopotamus?

The correct plurals are hippopotamuses and hippopotami.

---

Is hippopotami grammatically correct?

Yes. Hippopotami is accepted, although it is less common today.

---

Which plural is more common?

Hippopotamuses is more common in modern English.

---

Is hippopotamuses correct?

No. Hippopotamuses is incorrect.

---

Do dictionaries accept both forms?

Yes. Most major dictionaries list both hippopotamuses and hippopotami.

---

Which form should students use?

Students should usually use hippopotamuses because it is clearer and easier to understand.

---

Why do some words end in “-i” in plural form?

Some English words borrowed from Latin use “-i” endings, such as cacti and alumni.

---

Conclusion :

The plural of hippopotamus can be either hippopotamuses or hippopotami. Both forms are correct, but they are used in different ways. In modern English, hippopotamuses is the most common and easiest form to understand. It appears more often in schools, newspapers, websites, and everyday conversation.

The form hippopotami is still accepted and may sound more formal or traditional. Some writers use it in academic or literary contexts, but it is less common in daily communication.

If your goal is clear and simple writing, choose hippopotamuses. If you want a classic style, hippopotami also works. The most important thing is consistency. Pick one form and use it correctly throughout your writing.

Now you know the difference, the history behind the word, and which plural fits different audiences. This helps you avoid mistakes and write with more confidence in both formal and casual English.