Have you ever been in a classroom, reading a science book, or watching a debate, and someone says the word hypothesis? Maybe you nodded your head, but then you wondered: “Wait… what’s the plural of hypothesis?”

You’re not alone! Many people, even native English speakers, get stuck on words like this. The reason is simple: hypothesis doesn’t behave like everyday words such as cat (plural cats) or book (plural books). Instead, it comes from Greek, and that makes its plural form a little unusual.

Don’t worry we’re going to take it step by step. By the end of this article, you’ll feel completely comfortable with the word hypothesis, its plural form, and how to use it naturally in sentences. Let’s dive in together.

What Does “Hypothesis” Mean?

Before we talk about plurals, let’s make sure we understand the word itself.

A hypothesis is an idea or explanation that someone suggests before testing it. Think of it as a smart guess. Scientists often use hypotheses when they are trying to understand the world.

For example:

• A scientist might say: My hypothesis is that plants grow faster in sunlight than in shade.
• A student might write: My hypothesis is that sugar dissolves quicker in hot water than in cold water.

So, in simple words:

• A hypothesis is a possible answer or explanation.
• It’s not proven yet it’s something you test or investigate.

What Is the Plural of Hypothesis?

Now let’s get to the big question.

The plural of hypothesis is hypotheses.

Notice the spelling change:

• Singular: hypothesis
• Plural: hypotheses

The -is at the end changes to -es.

This might feel strange if you’re used to simply adding -s or -es to words. But this rule comes from Greek. Many English words borrowed from Greek follow the same pattern.

Examples:

• Crisis → Crises
• Thesis → Theses
• Analysis → Analyses

See the pattern? If a word ends in -is (and comes from Greek), its plural often ends in -es.

How Do You Pronounce “Hypotheses”?

Good question! The pronunciation can be tricky.

• Hypothesis (singular): hy-POH-thuh-sis
• Hypotheses (plural): hy-POH-thuh-seez

So in the plural form, the ending -ses is pronounced like -seez.

Tip: If you say it out loud a few times, it becomes natural. Try it now:

• One hypothesis.
• Two hypotheses.

Is “Hypothesis” Singular or Plural?

This is one of the most common confusions.

• Hypothesis is always singular. It refers to one idea.
• Hypotheses is always plural. It refers to two or more ideas.

Examples:

• Singular: Her hypothesis was correct.
• Plural: The scientists tested several hypotheses.

If you mix them up, your sentence may sound confusing or incorrect.

Why Doesn’t It Just Become “Hypothesises”?

Great question! The answer is history.

The word hypothesis comes from Greek. When English borrowed it (through Latin), it also borrowed its plural style. Instead of making it hypothesises, English kept the Greek way: hypotheses.

That’s why the spelling and pronunciation feel unusual. It’s not random, it’s tradition.

Real-Life Examples of “Hypotheses” in Use

Let’s look at some sentences to see how people actually use the plural form.

1. The teacher asked the students to write down their hypotheses before starting the experiment.
2. Many hypotheses have been proposed to explain climate change.
3. The committee considered several hypotheses, but none were fully convincing.
4. Darwin tested different hypotheses while developing his theory of evolution.
5. Scientists must reject or accept hypotheses based on evidence.

See how natural it sounds? Anytime you’re talking about more than one hypothesis, you should use hypotheses.

Comparing Hypothesis to Similar Words

It can help to compare hypothesis with other Greek-origin words:

• Thesis → Theses
  • Singular: His thesis focused on renewable energy.
  • Plural: All the students submitted their theses.
• Crisis → Crises
  • Singular: The company faced a financial crisis.
  • Plural: Several crises hit the economy that year.
• Analysis → Analyses
  • Singular: The scientist’s analysis was detailed.
  • Plural: The paper included multiple analyses.

By practicing with these, you’ll start to notice the pattern and remember it easily.

Fun Fact: Where Does the Word Come From?

Here’s something interesting!

The word hypothesis comes from the Greek word hypotithenai, which means “to put under” or “to suppose.” In ancient Greek, hypo- means “under” and thesis means “placing” or “proposition.”

So, originally, a hypothesis was an idea “placed under” consideration. That’s pretty cool, right?

It shows how old and respected this word really is.

Common Mistakes with “Hypothesis” and “Hypotheses”

Many learners (and even advanced speakers) make small mistakes with this word. Let’s clear them up.

1. Adding an “s” incorrectly
   • ❌ Hypothesises
   • ✅ Hypotheses
2. Mixing singular and plural
   • ❌ The hypotheses is correct.
   • ✅ The hypotheses are correct.
3. Spelling errors
   • Common misspelling: hypothisis or hypothesys
   • Correct spelling: hypothesis (singular), hypotheses (plural)

How Can You Remember the Plural Form?

Here are some simple memory tricks:

• Think of “hypothesis” as being like “analysis.”
  • One analysis → two analyses
  • One hypothesis → two hypotheses
• Practice saying it out loud:
  • “One hypothesis, two hypotheses.”
  • Repetition helps fix it in your memory.
• Write short sentences:
  • My hypothesis is simple.
  • Our hypotheses were tested.

By practicing both singular and plural together, you’ll naturally remember the difference.

When Do People Use Hypotheses in Real Life?

You might be wondering, “Do I really need to use this word outside science class?” The answer is yes!

Here are some everyday situations:

• In school or college: Students often write hypotheses for experiments.
• In business: Analysts may create hypotheses about customer behavior.
• In daily life: You might say, My hypothesis is that my friend is late because of traffic.

So, even though it sounds like a “big science word,” it can be useful in many parts of life.

Extra Examples for Practice

Let’s practice both singular and plural side by side:

• One hypothesis suggests that exercise improves memory.
• Different hypotheses suggest various ways exercise helps the brain.
• My hypothesis is that dogs are friendlier than cats.
• Our hypotheses about pets were tested through surveys.
• A single hypothesis can be tested in a lab.
• Several hypotheses were compared during the study.

The more examples you read, the more natural it becomes.

Fun Extras: Related Words

Here are some related words you might enjoy knowing:

• Hypothetical: Something that is imagined or suggested, not yet proven.
  • It’s just a hypothetical question.
• Hypothesize: The verb form, meaning “to suggest a hypothesis.”
  • The scientist hypothesized that water existed on Mars.

These are all connected to the same root word.

Conclusion

So, let’s quickly recap what we’ve learned in this friendly journey:

• Hypothesis means a suggested explanation or guess that you can test.
• The plural of hypothesis is hypotheses.
• Singular: hypothesis → Pronounced hy-POH-thuh-sis.
• Plural: hypotheses → Pronounced hy-POH-thuh-seez.
• Don’t add a normal -s. The -is changes to -es, following Greek tradition.
• Real-life examples show that this word is common in science, business, and even everyday conversations.
• Related words like hypothetical and hypothesize expand your vocabulary.

Next time you hear someone say hypothesis, you’ll know exactly what it means and if you need the plural, you’ll confidently say hypotheses.

Learning tricky plurals can be fun, especially when you see the patterns. And now, you’ve mastered one of the most famous ones.