Meaning of addendum

ad•den•dum

Pronunciation: (u-den'dum), [key]
— pl. -da -dums
  1. a thing to be added; an addition.
  2. an appendix to a book.
    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. Cf. dedendum.
    2. Also calledadden&prim;dum cir&prim;cle.an imaginary circle touching the tips of the teeth on a gear.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.
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