What’s the plural of “addendum”?
The plural of an addendum is addenda and addendums. An addendum, which is “something that has been added to a book, speech, or document”, is synonymous with appendix or supplementary material. Typically, addenda will include notes or material missing from the main text or work.
The report included several important addenda at the end.
Please read through the new addendums before the meeting.
The contract has three addendum that need approval.
They added a few more addendum to the original document.
Addendum has two plural noun forms: both addenda and addendums are correct, though the former is the original Latinate pl. n. form. Addendums, on the other hand, uses the standard pl. n. modifier in English by adding the –s at the end to show a plural. This standard form most likely came to be adopted as a plural for addendum over time, and through the consistent mistaking of addendums as the plural form.
Irregular plural nouns that end in um-/-a
Though unusual, addendum is by no means the only Latin noun that has sustained until Modern English. See the chart of irregular nouns that end in -um as a singular noun, and convert to -a as a plural:
| singular | plural |
|---|---|
| colloquium | colloquia or colloquiums |
| referendum | referenda or referendums |
| memorandum | memoranda or memorandums |
| curriculum | curricula or curriculums |
| addendum | addenda or addendums |
| symposium | symposia or symposiums |
Addendum in context (in sentences)
1. Alex added some personal remarks in the addendum of his letter.
2 .Maria’s article was written in 1965, but it was updated with an addendum in recent years.
3. I added an addendum to the report in which I highlighted certain legal issues that our company was facing.
4. It would be smart to add an addendum to your resume to highlight some of your areas of expertise.
5. If you read the addendum to Oliver’s biography, you will learn about the lesser known aspects of his life.
To make “addendum” plural, remember you *add* -a or -s: addenda or addendums.
Addenda/addendums in context (in sentences)
1. “We want to address the new addenda of the CMO,” said Glen Hartman, head of Accenture Interactive North America.
2. Make sure the lease contains signatures by both parties and all amendments, addenda, renewals, etc., are located and included. –OC Register
3. The lawyers introduced various addenda to the contract.
4. This includes the table of contents and any attachments or addenda .
5. They are extraneous addenda , and insidious ones at that.
Addendum synonyms
- appendix
- postscript
- afterward
- codicil
- excursus
- addition
- supplement
- complement
- epilogue
Origin of the word addendum
From etymonline on addendum, from Latin addendum, neuter of addendus “that which is to be added”.
What’s the difference between they’re, their, and there?
Work Sheet
According to the blog post, what is the primary meaning of “addendum”?
Which of the following is considered a correct plural form of “addendum” by the blog post?
The blog post mentions that “addenda” is the original plural form. Where does this form come from?
According to the post, what is a common mistake people make when trying to use the plural of “addendum”?
Which pair of words from the post follows a similar -um/-a plural pattern to “addendum/addenda”?
The report included several important at the end.
Please read through the new before the meeting.
The contract has three that need approval.
Maria’s article was written in 1965, but it was updated with an in recent years.
Make sure the lease contains signatures by both parties and all amendments, , renewals, etc., are located and included.
Frequently Asked Questions
What are the plural forms of addendum?
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Which addendum plural is traditional?
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Why does addendum have two plurals?
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What’s a common mistake using addendum?
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Example usage for addendum plurals?
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Yash, D. "What’s the Plural of Addendum?." Grammarflex, Jun 5, 2025, https://www.grammarflex.com/whats-the-plural-of-addendum/.
Sources
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Synonyms of addendum.
