I hate the term āturn on the forehand on a circleā, but I admit Iām biased because the only instructor Iāve had who has used terminology close to that drilled horses and students for large portions of the lessons (nominally) in this exercise, even though she actually wanted a shoulder in on a circle. Difference (briefly) being bend and intent of the exercise - the OP has not given us this info explicitly, so she could be asking about SI or leg yield or renvers on a circle of various diameters. Already on a circle and pushing the haunches out for ToF feel (straighter than the bend for the circle), makes me think LY on circle.
If the OP was doing whatās in that youtube video, @saschaās terminology is absolutely correct: āWorking turn on the forehandā (I havenāt heard āwalking turn on the forehandā before, but itās perfectly good), including the devolution to leg yield on a circle, imho.
I also do not like the term āturn on the forehand on a circleā because it does not make literal sense. It sounds like the forefeet should be processing around a circle, while the hind executes the turn on the forehand all the while. Like a pinwheel of pinwheels.