Ever tried to explain something about a door frame and found yourself saying, "You know, this bit. This bit right here that sticks out. The sticky-out-y part of the frame!" Well, let us teach you how to impress everyone with your door frame vocabulary.
First off, let's get something out of the way: the rabbet on the frame is not the same as a bunny rabbit, neither in spelling nor in function. With that out of the way, let's take a look at the bottom image.
First off, this is a cross section of a hollow metal frame, but the same parts can also be found on wood frames.
Not all frames will have the return or backbend, but they are quite common so it's important to know what you're looking at.
Next, notice that the "stop" labeled in this picture is different that what we all colloquially call a stop. The actual stop portion of the frame is more rightly called the soffit (and we can feel like Bob Vila when we say it) and the stop actually refers to the side of the soffit where the door actually hits.
The rabbet (again, not the fluffy one with ears) is the flat portion on either side of the soffit.
Rabbit, not Rabbet 
Frame Parts