Please explain in simple terms...brightness

Could someone please explain what some adjectives mean? I'm reading descriptions such as brightness and transparent, but I have only a basic knowledge of sound qualities. Is there a website to educate myself in this area?

I listen to classical, opera, and jazz, and my room size is 12x20. Currently I own a simple system: Yamaha components (CD, Tuner, and Amp.), with a pair of Kipsch (RF-5) floorstanders. It was a drastic improvement from what I lived with before, but I'll need better sound because I'm not hearing the "color", or is it "brilliance" in the voices, especially when a choir is heard. Maybe I'm not doing my speakers justice with the Yamaha components, however I anticipated upgrading those at some point.

Now I'm planning on overhauling my whole system, and from what I've read, I'll need to give myself plenty of time to experiment and research what's best for my situation.

One thing I couldn't get over were those high-hats coming from the Tractix horn; I'd swear there was an actual drummer sitting between the speakers if I closed my eyes.

Thanks for all the knowledge that's shared here.

David (Hftd, CT)
Try this list of terms for reference.
As you'll see, brightness is usully associated with a rise in amplitude resonse in the mid-high region.
Here's another reference source, this from Stereophile:

Gregm provides a fine definition for brightness. IMHO, brightness tends to sound great at first (wow, listen to that detail!) but grates on the nerves after more extended listening.
excess treble energy.
Just blast an average car stereo with rock music and that harsh hi pitched sound that is like an ice pick to the brain is an example of brightness - an extreme example, but you'll know brightness after that.

I tend to agree with the link that Gregm provided over the definition that Stereophile presented. That is, brightness is an elevated output level in the treble region. According to Stereophile, they state that brightness and brilliance are the same thing. They go onto explain that these terms apply to the output levels and transient response between 4KHz and 8 KHz. Since transient response ( brilliance ) doesn't necessarily directly correlate with with average output levels ( tonal balance ), they are confusing two different terms down into one in this specific instance. Sean