What is the definition of "addendum" or "addenda"?

Question

The word addenda, and addendum used in a bid process.

Answer 1

addendum |əˈdendəm|
noun ( pl. -da |-də|, -dums)
1 an item of additional material, typically omissions, added at the end of a book or other publication.
2 Engineering the radial distance from the pitch circle of a cogwheel, worm wheel, etc., to the crests of the teeth or ridges. Compare with dedendum .

ORIGIN late 17th cent.: Latin, ‘that which is to be added,’ gerundive of addere (see add ).