Whats the Plural of Paralysis: Understanding Grammatical Nuances

Paralysis and Paralyses — See the Pattern

Look at these two sentences. Can you see the difference?

• The patient has one paralysis in his left arm. (one = singular)
• The doctor studied three different paralyses. (three = plural)
• Sleep paralysis is very common. (one type = singular)
• Both paralyses were caused by the same injury. (both = plural)

Did you see the pattern? When there is one, we say paralysis. When there are two or more, we say paralyses.

The ending changes like this:

The -sis at the end changes to -ses. That is the only thing that changes.

When to Use Paralysis and When to Use Paralyses

This word comes from Greek. In Greek, words that end in -sis always change to -ses in the plural. This rule works the same way every time.

Use “paralysis” (singular) when you talk about one:

• The accident caused paralysis in her legs.
• Sleep paralysis happens when you wake up but cannot move.

Use “paralyses” (plural) when you talk about more than one:

• The study looked at several paralyses from different causes.
• Doctors treated two paralyses in the same patient.

Easy way to remember: Many English words follow this same Greek pattern. If you know one, you know them all:

How to Use Paralysis and Paralyses in Real Life

• My grandmother had paralysis on one side of her face for a week. (one case — singular)
• He read about sleep paralysis and now he understands what happened to him. (one type — singular)
• The news said the cold weather caused several paralyses of city services. (several — plural)
• Decision paralysis is when you have too many choices and cannot pick one. (one idea — singular)
• The hospital treated different types of paralyses after the earthquake. (different types — plural)

You are doing great. Now let us look at the mistakes many learners make.

The Most Common Mistake With Paralysis

Even advanced learners sometimes try to add -es to the full word. They write “paralysises” because that is how most English plurals work. Do not worry — this is a very normal mistake.

How to remember: You do not add letters. You swap the ending. Take off -sis, put on -ses. That is it.

Other words that work the same way: crisis → crises, analysis → analyses, thesis → theses, diagnosis → diagnoses.

Test Yourself: Paralysis or Paralyses?

Choose the correct answer for each sentence. Click Check to see if you are right.

Keep Going — You Are Building Something

You just learned how to make the plural of paralysis. That is one more Greek-style plural you will never get wrong again.

But here is something interesting. You probably know the word diagnosis — your doctor gives you one when you are ill. But what happens when a doctor gives two of them? Is it “diagnosises”? “Diagnosises”? Or something else?

Next lesson: What Is the Plural of Diagnosis?

Sources

Paralysis synonyms.

Paralysis examples in sentences.