What is a propietary trading firm or Trading Arcade

Hi Im new in this.
I know that probabily there is many people that have ask the same but I can not find it. Also I have read the definition but still not clear to me.

So if someone could explain me in a simple way what are:

Trading Arcade
Prop shop
Propietary Trading Firms.


Thanks

Its a place where poor traders go who can't afford to trade a decent size out of their own pocket and they share a big office with other traders in hope they can learn to trade by listening to others!

Thanks but still not enoguh information for me to know what kind of companies they are

T2W Day Trading & Forex Community
http://www.trade2win.com/boards/trading-arcades/17603-prop-trading-house-trading-arcade.html
Trading Arcades - T2W Day Trading & Forex Forums
Trading arcade - Traderpedia
Proprietary trading group - Traderpedia

My first answer is still the best though!