Yes, all CD ROM , DVD Rom are optical disc since they use laser light or electromagnetic wave.
A DVD ROM is a "Read only Memory*" it is the disk itself and as such it cannot burn anything. A DVD reader can only read DVDs. A DVD writer can write som recordable DVD formats.
NO, DVD rom can only read DVD discs.
Yes. Although there are more high capacity disks out there.
DVD (an original single sided, single layer, DVD-ROM)