Fictitious forces is the name given (amongst others which you most probably know them by) to describe the perceived changes in motion of objects within non-inertial systems.
Fictitious forces is the name given (amongst others which you most probably know them by) to describe the perceived changes in motion of objects within non-inertial systems. A specific example would be helpful. I do know of some "forces" and "motions" in physics which are strictly conceptual but don't actually exist in the math (or reality), but I'm not sure if we're talking about the same thing.