Multi border dvd?

Hi, what’s a multi border dvd?

In user guide of a dvd player I’ve found this:
[I]
For DVD-R and DVD-RW multi border, Video CD
only finalised disc are supported.
(Formats 1.0, 1.1, 2.0)

For DVD+R and DVD+RW multi border
both ifinalised and unfinalised disc are NOT
supported.[/I]

Thanks

multi-session