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What is the Meaning of “Addendum”?

Addendum
/əˈdɛn.dəm/
noun C1 Tier 5 (Rare) formal academic

additional material appended to a written work after its main text to supplement or clarify content

Definition of Addendum

Quick Meaning of Addendum

additional material appended to a written work after its main text to supplement or clarify content

Detailed Definition of Addendum

a section added to the end of a book or document containing extra information

How to Pronounce Addendum

IPA: /əˈdɛn.dəm/
ad den dum

Stress pattern: oOo (3-syllable word).

Tip: Stress the second syllable: uh-DEN-dum. The 'um' at the end is pronounced like the 'um' in 'sum'

Watch out: ad-DEN-dum (stressing first 'a') or ADD-en-dum (using English plural form 'addendums')

Full pronunciation guide for “addendum” →

Origin and Etymology of Addendum

From Latin addendum, gerundive of addere (to add) — literally 'that which must be added'

How to Use Addendum in a Sentence

Each example shows “addendum” with a CEFR level so learners can pick examples that match their fluency.

Synonyms and Antonyms of Addendum

Common Synonyms for Addendum

Smart Synonyms for Addendum — When to Use Each

appendix
longer, more detailed addition
supplement
material added to complete
attachment
document added separately

Antonyms of Addendum

See all synonyms for “addendum” →

Common Collocations with Addendum

These phrases pair with “addendum” in everyday English:

  • add an addendum
  • appendix and addendum
  • contract addendum
  • final addendum

Common Mistakes When Using Addendum

Even fluent speakers slip up with “addendum”. Here’s how to avoid the most common errors:

✗ Wrong: The addendum are attached
✓ Correct: The addendum is attached
Why: Addendum is singular; plural is addenda. When singular, use 'is'; when plural addenda, use 'are'
✗ Wrong: I found two addendums in the book
✓ Correct: I found two addenda in the book
Why: The correct Latin plural is addenda, not addendums, though addendums is sometimes used informally

Words Confused With Addendum

  • Addendum vs Appendix: Both add extra info; appendix is longer and more detailed; addendum is brief supplementary note

Other Forms of Addendum

Frequently Asked Questions About Addendum

What is the meaning of "Addendum"?

additional material appended to a written work after its main text to supplement or clarify content

How do you pronounce "Addendum"?

The IPA is /əˈdɛn.dəm/. Stress the second syllable: uh-DEN-dum. The 'um' at the end is pronounced like the 'um' in 'sum'

What part of speech is "Addendum"?

"Addendum" is a noun at C1 level (Common European Framework).

What are synonyms for "Addendum"?

Common synonyms include appendix, supplement, attachment.

How do you use "Addendum" in a sentence?

Try writing a short sentence about a personal experience using "addendum".

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