Registration and related terminology is VERY state specific.
I can tell you that here in Montana ALL trailers are given PERMANENT license plates, regardless of type or size, so it doesn't matter what it is called on the registration, and ALL trailers over 3000 lbs. GVW must have brakes on all wheels.
But, that doesn't do you a bit of good, since you are in Kentucky.
The Kentucky Department of Motor Vehicles or Motor Vehicle Department or whatever it is called (that is different in different states, also) will be able to answer your questions.