addendum

[ uh-den-duhm ]

See synonyms for addendum on Thesaurus.com

noun,plural ad·den·da

[uh-den-duh] /əˈdɛn də/ for 1, 2; ad·den·dums for 3.

a thing to be added; an addition.
an appendix to a book.

Machinery.
- the radial distance between the tip of a gear tooth and the pitch circle of a gear or the pitch line of a rack.: Compare dedendum.
- Also called addendum circle. an imaginary circle touching the tips of the teeth on a gear.

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

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use addendum in a sentence

Overall, the plurality of voices—of young Helga and the author making revisions and addendums to the text decades later—mesh well.
This Week’s Hot Reads: April 29, 2013 | G. Clay Whittaker, Jen Vafidis | April 29, 2013 | THE DAILY BEAST
He knew how I hated a talkative person, and yet he stampedes into the conversation with his amendments and addendums of syntax.
Heart of the West | O. Henry

British Dictionary definitions for addendum

addendum

/ (əˈdɛndəm) /

nounplural -da (-də)

something added; an addition
a supplement or appendix to a book, magazine, etc

the radial distance between the major and pitch cylinders of an external screw thread
the radial distance between the pitch circle and tip of a gear tooth

Origin of addendum

C18: from Latin, literally: a thing to be added, neuter gerundive of addere to add

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

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