What's THAT key...?

[Andy]

Hi guys :)

I've looked all over the 'Net for an answer to this, but can't find one:

What's the key that looks like a hat (a basic upwards-pointing arrow
head) with a line above it? It's next to the right command key, and
arrow keys.

According to some stuff I found on the Web, it's a "meta" key (whatever
that is) or "enter" key, which I can only guess is for the Terminal or
some other special purpose. Is it supposed to act as a "break" key to
interrupt a process, or produce a "return" character, or what?

Maybe I'm confused because it's a "whatever the heck you want it to be"
key, hence some people calling it a "meta" key. What can I do with it??

I dunno. Is there an official answer to this one? In fact, where is a
good place to find out about these things - I don't think Apple's site
is that great for searching, and the documentation doesn't provide
answers for a few things I find myself asking. (At least, I don't THINK
it does - I've got a lot of new stuff to experiment with on my new
TiBook, so maybe I can't see the wood for the trees!!)

Thanks guys :)

Andy