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addendum

[ uh-den-duhm ]
/ əˈdɛn dəm /
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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.

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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

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
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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