What is the difference between DVD - R, DVD +R , DVD-RW ,DVD+RW

There are different types of DVD disk formats available in market.
i. DVD -R
ii DVD +R
iii DVD- RW
iv DVD +RW
v. DVD ROM
The difference between DVD - R and DVD -RW or DVD +R or DVD - RW is, DVD - R or DVD + R types of DVD disks are only one time recordable...