I wouldn't tell you to sit down or shut up, clear concise communication is important and using the correct word can often make things much easier.
Though, I think your definition of a catapult is more accurately a Mangonel or an Onager. I believe the typical view of a catapult is one of those two. From some quick reading I think the main difference between the various catapults was the trajectory they launch their projectiles at. A trebuchet had a very high trajectory whereas a Mangonel had a low trajectory.
Sorry to be getting so off topic. Im a huge history nut.