Hi,
What’s the difference between “stadium” and “arena”?
Thank you very much.
Nessie.
I think they mean the same thing for modern usage. The difference could be as stadium from Greek while arena from Latin, that’s why the latter used to mean the area in the center of an ancient Roman amphitheater where contests and other spectacles were held. Just my two cents.
Haihao is right. The two words mean the same thing. In fact, when I looked up “stadium” in the dictionary, it used the word “arena” to define it.
Hi Nessie
It seems to me that a difference might be that ‘arena’ is used figuratively more often than ‘stadium’. For example, “He threw his hat into the political arena”.
.
Hi Nessie,
To my mind ‘stadium’ is essentially the building in which people stand/sit to watch events/shows/ sports. The arena is the open part where these events take place as in the concept of the Roman amphitheatre - like the one in Verona. Incidentally I went to an opera performance once in Verona and at the end of the performance as we were leaving, a serious voice intoned: Please do not throw your seat cushions into the arena. And this was in Italy! What an invitation!
Alan
Thank you very much for your help, everybody :D:D:D
Isn’t it an interesting experience? :P;)
(By the way, how I admire you, Alan 
you must have travelled around the world! 8) 
)
I sort of second this feeling also. Technically, an arena should have sand (the word comes from the Latin ‘harena’, meaning ‘a sandy place’), but anymore that’s not always so. There’s many a grassy arena (funny if you think about it) around today.
At least in my part of the world, the place where the activity (rodeo, race, fight, or game, etc.) takes place is normally called the arena, while the seating area is referred to as the stadium.
It’s somewhat misused nowadays, I think, because you’ll often hear people referring to common free-standing outdoor aluminum benches as well as concrete steps with seating as the stadium, without being enclosed or part of a larger building. But if there’s one consistent feature in any language, it’s the fact that the language changes and evolves according to the whims and usages of the speakers.
I sort of second everything above. :lol:
I agree with the idea that ‘stadium’ has a general sense of being the place where spectators sit, while ‘arena’ has more of a sense of the area that spectators look at.
In addition, I tend to associate certain types of sports or events with each word. For example, I associate baseball and football games with “stadiums”, and ice hockey, concerts and even conventions with “arenas”.
.
Thanks a lot once more, everybody 
Hi Skrej,
May I know how native speakers call those kinds of so called “stadium”? (correctly)
(they are very common here for music shows, you know :P)
Probably the most common term for them is ‘bleachers’, although they’re frequently called ‘stands’ also. You may also hear the term ‘grandstand’, but grandstands are usually larger, often with some sort of roof or covering (but no walls). You’ll hear the same two terms used even within the same geographical region. I myself use the two terms interchangeably, although I sometimes seem to use the word ‘bleachers’ for the smaller sets, but not always.
That being said, the following sites will show that there’s a lot of overlap between the terms ‘grandstand’ and large ‘bleachers’. Two people might call the same thing by different names.
www.bleachers.net/
http://www.southernbleacher.com/
http://www.getseating.com/photos.htm
http://www.4specs.com/s/13/13-3430.html
The wiki entry theorizes some origins of the word.
Thanks a lot, Skrej. I only have one more question: The word “bleachers” refer to a set of seats at a sports ground (only the seats), so can it be used to refer to the whole “stadium”?
Thank you very much.
“Bleachers” are the wooden or metal planks that are used as seats in stadiums.
There is a very interesting novel called “Under the Bleachers” by Seymour Butz.
Thank you very much, Jamie 
Now I have another question: as Skrej said, the term “stadium” is not suitable for that so-called “stadium” with just bleachers (not a building with a roof - or perhaps it has a roof but it’s not a building like a standard stadium) and so, if “bleachers” only refers to the set of seats, not the so-called “stadium”, then what is that kind of so-called “stadium” called?
Thank you very much.
Nessie.
Hellooo???
I think the use of one term over the other has mostly to do with the type of event. Football and baseball are played in a stadium while basketball and hockey are typically played in an arena
Also the word arena in spanish, italian even in latin means “sand”, which was useful as the primary surface where gladiators battled, to absorb the blood. Hope this help!!!