Ah thank you for the first excellent question to this new section of the forum. This is a hobby site more than anything, kind of my own personal place to give to the community of geeks and budding geeks. It also makes a nice spot for me to nest down in during the harsh winter months.
I haven't done ANYTHING with Oracle since 2002 I think? It has been a number of years now, I was with a telecommunications company which is a polite way of saying that I was a Jr. Systems Administrator for a company that provided outsourced phone support and telemarketing.

Ah the evils we humans will do for money.
Since reading your post an hour ago I keep going on mental trips back in time. We were state of the art, the bleeding edge, and even had as AS/400. I think it might have had the name changed to iSeries by then though.
As I recall one of the stuffed shirts had gotten it into their head that the mainframe was dead (yet this was the same suit that thought the thin-client was a bad idea) and as I was leaving they were converting the remainder of the 750 seats to (really) Windows ME. I kept up with an older friend who remained with the company for a while and I understand that it didn't go quite as bad as I'd expected it would but it is a moot point as just about a year later they shut the shop down, sold off the property, and moved to India and one of the South Pacific islands.
But I digress.
Somewhere in this slightly rusted brain of mine I may have more information available.
Let me see if I can remember - do NOT take this as correct but rather verify it. Please? It has been a LONG time.
In your particular question the (+) means an outer join?
TEAMNO TNAME
---------- ----------
1 Team1
2 Team2
PLAYERNO TEAMNO PNAME
---------- ---------- ----------
111 KGIII
The query:
select d.*,t.teamno,t.pname
from dept d,team t
where d.teamno=t.teamno(+);
That would return no values for Team2 even though there were no entries in Team2 and the returned data would be useful for someone who wants to get the complete roster listings. However simply dropping the (+) sign will return will give the values for Team2, which hasn't any entries in this case, and would be useful for seeing what teams needed additional players.
The outer join was included so that the stuffed suits could ask the managers questions about all the departments and the managers wanting to be evil and give them a returned value for all the information in a table regardless of it having any data. An outer join returns information about all the rows in a table even if they don't contain any information.
I'm pretty sure I buggered the code up though. You'll really want to verify that.