I have known some manufacturers refer to this part as the disc table.
Colin, January 2008
I don't think there's a technical name for it, but I do know that it's just considered part of the "motor assembly." I would call it the "disk mount," or something like that.
Jus out of sheer curiosity, why do you ask?
Patrick Sewell, January 2008
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I can answer this question...
what is the little rubber mat that spins the dvd called?