What is the difference between a journal, a magazine and a .

What is the difference between
1. a journal,
2. a magazine,
3. a proceeding (of IEEE or others)
4. a transaction (of IEEE or others)
5. a letter.

I am asking this in context of IEEE publications.

Also, I have seen a number of publications with "volume" written on it... What does this mean?

Thank you.

Periodicals are grouped in volumes. By convention, a volume is one year's worth of issues, which need not begin and end on a calendar year.