Tracking Shots and Dolly Shots

Note: These are used somewhat casually as interchangable terms.  Technically, a "tracking shot" ought to involve a camera and camera operator riding on a frame that rolls on actual "tracks" like a railroad car.  A "dolly shot" should involve a camera mounteed on a free rolling "dolly" pushed through the set by helpers while the camera operator rides.  Gradually, the terms have grown confused by the practice of using "to track" or "tracking" ot "to dolly" or "dollying" to describe any movement of the camera relative to its subject ("the camera tracks left to follow them"; "the camera dollys left to follow them").