from The American Heritage® Dictionary of the English Language, 4th Edition
- transitive v. To add (supplementary recorded sound) to a previously taped musical recording especially in order to heighten the total effect.
- n. Additional recorded sound that is blended into a musical recording: instrumental overdubs.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- v. To record a part along with an already recorded part or parts.
- n. An overdubbed part.
over- + dub (in the sense of double) (Wiktionary)