"horizontally opposed"

[gottacatchup]

I was having an arguement with a friend of mine who drives a 3000GT about the definition of horizontally opposed. I'm pretty sure its the boxster engine configuation where the cylanders oppose eachother. HE claims it relates to the position of the engine in the car. Meaning that horizontally opposed engines are mounted so the cam points across the car perpendicular to the direction of travel.

I just want to make sure i'm not a complete idiot and confirm my belief that he is. Any help would be greatly appreciated.