Document on table definition and meaning of value

Where can I find the document to get the table definition and meaning of the value?

For example, v$session_wait, how many different value could the columnh state have? select distinct state from v$session_wait showed two: waited short time and waiting. Are these two the only two value could be in that column? select distinct wait_class from v$session_wait shows network and idle, but what are these value mean?

There are so many other tables I have question about eg fnd_concurrent_requests.

Please advise. Thank you very much.