The 'Computer Hardware Acronym List' is helpful in listing the terms but doesnt have enough detail, just acronym & full title.
As far as RW, RAM and ROM go.. they are fairly well explained by the list:
R = Recordable (a cd or dvd which can be written or 'burned' only once)
RW = ReWriteable (a cd or dvd which can be written and then erased & re-written)
ROM = Read Only Memory (a cd or dvd which can be read but not written)
RAM = Random Access Memory - this is a tricky one. As far as DVD-RAMs go the name is a bit misleading, and some ppl with think of normal RAM immediately but basically you should think of DVD-RAM as a DVDRW but with more features and advantages.
If you wanna get a better grip on it try this:
http://www.afterdawn.com/glossary/
or just wiki the bugger!!