What’s the Plural of Memorandum: Understanding the Variations

Memorandum, Memoranda, Memorandums — See the Pattern

A memorandum is a short written message, usually at work. People often call it a “memo” for short. Look at how the plural works:

• The boss wrote one memorandum about the new rules.
• The office received three memorandums this week.
• The lawyers exchanged several formal memoranda before the meeting.
• I always keep my old memos in a folder on my computer.

Did you see the pattern? There are two correct plurals — and a handy short form too:

When to Use Memoranda and When to Use Memorandums

The word “memorandum” comes from Latin. In Latin, words that end in -um change to -a in the plural. That is why “memorandum” becomes “memoranda.”

But in modern English, we also just add -s to make “memorandums.” Both forms are correct. Here is when to use each one:

• Memoranda — use this in formal writing: law, business reports, official letters
• Memorandums — use this in everyday writing: office emails, quick notes, normal conversation
• Memos — the most common form in spoken English and casual writing

Easy way to remember: If you are writing something formal (like a legal document), use memoranda. For everything else, memorandums or memos is fine.

Other Latin words follow the same -um → -a pattern:

Real-Life Examples With Memorandum and Memoranda

• The manager sent a memorandum about the new work hours. (one message — singular)
• We received two memorandums from head office this morning. (more than one — English plural)
• The government released several memoranda on the new policy. (more than one — Latin plural, formal)
• Did you read the memo about Friday’s meeting? (short form — very common in spoken English)
• There are too many memos in my inbox — I cannot read them all! (short form plural)

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

The Most Common Mistake With the Plural of Memorandum

Even advanced English speakers get confused by Latin plurals — so if you mix them up, you are not alone. The biggest mistake is adding -s to the Latin plural and writing “memorandas.” This is not a real word.

How to remember: You have two choices for the plural — the Latin way (change -um to -a) or the English way (add -s). Never mix them together. And when you only mean one, always use memorandum.

Test Yourself: Memorandum, Memoranda, or Memorandums?

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

Keep Going — You Are Building Something

You just learned the plural of memorandum. That is one more Latin plural you will never get wrong again.

Did you know that formula also comes from Latin — and has the same kind of double plural? Is it formulas or formulae? And does it matter which one you use?

Next lesson: What’s the Plural of Formula?

Sources

Definition of memorandum.

Sentence examples memorandum.

Synonyms for memorandum.

Origin of memorandum.