addendum

American  

[uh-den-duhm] / əˈdɛn dəm /

noun

plural

addenda, addendums

1. a thing to be added; an addition.

2. an appendix to a book.

3. Machinery.

   1. the radial distance between the tip of a gear tooth and the pitch circle of a gear or the pitch line of a rack.

   2. Also called addendum circle.  an imaginary circle touching the tips of the teeth on a gear.

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addendum British  

/ əˈdɛndəm /

noun

1. something added; an addition

2. a supplement or appendix to a book, magazine, etc

3. the radial distance between the major and pitch cylinders of an external screw thread

4. the radial distance between the pitch circle and tip of a gear tooth

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Etymology

Origin of addendum

First recorded in 1785–95; neuter singular of Latin addendus “that which is to be added,” gerundive of addere “to add”; see add

Explanation

When you make an addendum to a document, you are adding text to the end. Addenda tend to be serious business as they're added to contracts, reports, and studies. There is nothing dumb about an addendum; often an addendum makes a document "smarter" by adding more information. If you did a science report on plant growth and found that after your study was complete, the plant flowered in an unusual way, you might describe that as an addendum to your report. Fun fact: the plural of addendum is addenda.

Example Sentences

What may leaders have told these members who had concerns about the rules, or the Secret Three-Page Addendum?

From Slate • Jan. 9, 2023

The justice department said the Federal Execution Protocol Addendum, which closely mirrors protocols currently used in Georgia, Missouri and Texas, replaces a three-drug cocktail previously used in federal executions with a single drug: pentobarbital.

From The Guardian • Jul. 25, 2019

“Apparently no one wanted to tell Minister Doskozil that no grounds for suspicion existed,” ORF and Addendum, which also obtained the internal report, said, quoting the unnamed prosecutor’s comments at the meeting.

From Reuters • May 16, 2019

We discussed a book Bill wrote, called The Final Addendum, described, in part, as: “The approach to the creation event with mathematical correlations in Bible observations, based on its accurate connection with real historical events.”

From Salon • Feb. 10, 2019

A single $60* fee will be required for a renewal registration using Form RE and Form RE Addendum.

From Supplementary Copyright Statutes, US Copy. Office by Library of Congress. Copyright Office

Related Words

• appendix
• postscript