You are right "play" can mean anything, in my case the steering wheel had about 15 degrees to either side of play, this randomly caused the VSC to lock the tires as the car computer thought the car was in a skid when entering gentle turns on the road and nearly got me into several accidents...
to test drive in a straight line move steering right and left, notice the amount of movement until the wheels actually respond, the bigger the play the more worn the RP is.
I have 160K on my LX470, the rack and pinion had so much play it caused VSC to activate and nearly crash on several occasions so replacing the rack and pinon and control arms is not a bad idea. I had to fork $2800 to the Riverside Lexus dealer. To replace AHC I purchased the OME torsion bars and...