Orchestra vs. Symphony-whatcha got?

I'm headed to the Symphony Orchestra tonight-a Spoleto event in Charleston. Pretty excited about it. The question was posed-"What's the difference between an orchestra and a symphony orchestra?" Beats me. I looked it up...

The basic of the basics is that all symphonies are orchestras, but not all orchestras are symphonies.

Orchestras can vary in size and instrumentation. They can be as small as 4-5 members and then would be called a chamber orchestra because they are small enough to play inside of a chamber, office, etc. When they are big enough to need a concert hall they become an orchestra or a symphony orchestra.

But...they earn the right to be called a symphony orchestra when they have the following qualifications:

1. They have four sections of instruments: strings, woodwinds, brass, and percussion.
2. They have the capability to play a symphony. Which brings us to another definition and that would be the definition of a symphony.

Symphonies are long pieces, usually of three or more movements, written for orchestras with full percussion sections, piano, harp, bassoons, oboes, an organ, a special guy to play the triangle, etc.

To sum it all up-symphonies are orchestras on a very large scale.

I definitely feel like I can attend this event tonight and talk with the lady sitting next to me who will most likely be a regular attender of these things. Whew! Didn't want to seem uninformed on this important topic.