1. overdub - Noun
2. overdub - Verb
overdub (third-person singular simple present overdubs, present participle overdubbing, simple past and past participle overdubbed)
(sound engineering) To record a part along with an already recorded part or parts.
The rhythm guitar part is live, but the solo was overdubbed.
overdub (plural overdubs)
(sound engineering) An overdubbed part.
The rhythm guitar part is live, but the solo is an overdub.
One peculiar consequence was that it was possible to overdub additional sound onto a recording being played back. Source: Internet
Using a multitrack system, a band and their music producer could overdub many layers of instrument tracks and vocals, creating new sounds that would not be possible in a live performance. Source: Internet