What the hell?

This was the opening paragraph of a story in the Ft. Worth Star Telegram:

Arlington police want help from the public in identifying the man who, armed with an assault-style pistol, recently robbed a GameStop store in the 2500 block of East Arkansas Lane

So, I am a fairly educated gun owner and would like to know what the hell is an "assault-style" pistol? Is this another term for a machine pistol or a new anti-gun jab by the media types?