Dictionary.com

addendum

[ uh-den-duhm ]
/ əˈdɛn dəm /
Save This Word!

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

QUIZZES

QUIZ YOURSELF ON THE MANY TYPES OF NOUNS

They're everywhere you turn, but can you identify the 10 types of nouns easily? This quiz will test your mettle against singular, plural, concrete, abstract, common, proper, collective, compound, countable, and uncountable nouns!
Question 1 of 7
Shoelaces, rainbow, toothpaste, and haircuts are all what type of noun?

Meet Grammar Coach

Write or paste your essay, email, or story into Grammar Coach and get grammar helpImprove Your Writing

Meet Grammar Coach

Improve Your Writing
Write or paste your essay, email, or story into Grammar Coach and get grammar help

Origin of addendum

1785–95; neuter singular of Latin addendus to be added, gerundive of addere to add
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

Example sentences from the Web for addendum

  • 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|DAILY BEAST
  • He knew how I hated a talkative person, and yet he stampedes into the conversation with his amendments and addendums of syntax.

British Dictionary definitions for addendum

addendum
/ (əˈdɛndəm) /

noun plural -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

Word Origin for 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
FEEDBACK