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.
QUIZ
QUIZ YOURSELF ON "WAS" VS. "WERE"!
Were you ready for a quiz on this topic? Well, here it is! See how well you can differentiate between the uses of "was" vs. "were" in this quiz.
Question 1 of 7
“Was” is used for the indicative past tense of “to be,” and “were” is only used for the subjunctive past tense.

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. 2022

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|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