What do you call the camera lens with circle in 2 halves that line up when focused correctly?

Split image focus -- think of it as the way your two eyes move independently as they try to focus on an object as it is brought closer to your nose. The point where they focus is related to the distance and that's how the focus is set.

SLR - single lense reflex

The light entering the lense of the camera is divided into two by a partially mirrored glass plate. One goes into the part where it is captured on film, the other to your eyepiece.

SLR,many older 35mm cameras say(Cannon Tlb or Olympus OM2)also have a meter at the right of the viewfinder with a circle and line which need to match up for the correct F stop and shutter speeds to give the optimal picture in any given light conditions.

Split focus

This is called a reticule. I suppose you could ask for a "reticulated lens". That is the specific answer to your question. The others have done a good job of describing the system of which this is a part.