Addenda or Addendum – How to Use Each Correctly

/ October 15, 2019/ Usage

addenda versus addendum

What is the Difference Between Addenda and Addendum?

Addenda and addendum are the plural and singular forms of the same noun, respectively.

Addenda is a plural noun that means things that are added to something else.

  • The meeting will address several addenda from the members.

Addendum is a singular noun that means something that is added or an appendix to a book.

  • I need to revise that document with an addendum.

Now, let’s go over the specific ways each of these words are used.

Using Addenda in a Sentence

When to use addenda: Addenda is the plural form of addendum, which means a thing which is added to another thing.

For example,

  • The lawyers introduced various addenda to the contract.
  • New discoveries meant that the police had to attach several addenda to the crime report.

Most English plural nouns end with the letter s. However, a few words with direct Latin roots maintain the Latin rules for the plural form. Addenda is one of these, along with stratum/strata, criterion/criteria, phenomenon/phenomena, memorandum/memoranda, and several others.

Because these types of words are so rare, you may find some sources that list addendums as a possible alternate spelling of addenda. However, addenda is the classical plural spelling, and therefore the better one to use. Just be aware that you may also see addendums.

Using Addendum in a Sentence

When to use Addendum: Addendum is a singular noun that refers to something, especially additional text or documents, added to something else. Usually this added content is included at the end of a document. It can also refer to the appendix of a book.

For example:

  • The book is almost complete, but it should also contain an addendum.
  • The newly discovered letter will be included as an addendum to the article.

This is an academic word, so it is not common in casual conversation. It is appropriate to use in business, academic, or formal contexts.

Remembering Addenda vs. Addendum

The easiest way to remember which of these words is singular and which is plural is to think of other similar Latin word pairs that you already know, that follow the same pattern. One well-known example would be bacteria, which is plural, and bacterium, which is singular.

However, if you are not familiar with any other similar pairs, there is another method you can use. Addendum contains the letter u, like the Spanish word for one: uno. Addenda ends with the letter a, like the words and phrases a few, many, and several, all of which signify something plural.

If all else fails, you can remember that addenda is an uncommon word, and it has an uncommon ending for a plural noun.

Outside Examples

  • “We want to address the new addenda of the CMO,” said Glen Hartman, head of Accenture Interactive North America. –Wall Street Journal
  • Make sure the lease contains signatures by both parties and all amendments, addenda, renewals, etc., are located and included. –OC Register
  • An addendum released Wednesday includes five staffers never identified before and outlines abuse that occurred up to 2009. –New York Post
  • And on Friday, the Oklahoma State/A&M Board of Regents approved an addendum to Gundy’s contract that includes a $675,000 pay increase, bumping his salary to $5 million per year. –New York Daily News

Quiz: Addenda vs. Addendum

Instructions: Fill in the blank with the correct word, either addenda or addendum.

  • The book is almost finished. I just need to add a single ______________.
  • The author has included so many ______________ that the document is twenty pages too long.
  • You might want to include an _______________ showing the copy of the original document.
  • I’m sorry. I didn’t see that there was an ________________ at the end of essay.
  • The judge ignored all of the multiple ________________ to the document.

Article Summary

Should I use addenda or addendum? These are simply two forms of the same word. However, because one is plural and one is singular, you cannot interchange them.

  • Addenda is the plural form, and means additions, especially to a book or other written document.
  • Addendum is the singular form of addenda.

Using the information above can help to ensure that you don’t mix up these two words.

Quiz Answers

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