[ ə'dɛndəm ]
■ noun ( plural addenda -də )
1》 an extra item added at the end of a book or text.
2》 Engineering the radial distance from the pitch circle of a cogwheel or wormwheel to the crests of the teeth or ridges. Compare with dedendum .
Origin
C17: L., 'that which is to be added', gerundive of addere (see add ).