A shot using a lens whose focal length is adjusted during the shot. A zoom shot is not a camera move. When you use a zoom shot you can capture subjects from far away.
Zooms are sometimes used in place of tracking shots, but the differences between the two are significant. A zoom normally ends in a close-up, a zoom-back in a general shot. Both types of shot imply a rapid movement in time and space, and as such create the illusion of displacement in time and space. A zoom-in picks out and isolates a person or object, a zoom-out places that person or object in a wider context. A zoom shot can be seen, therefore, as voyeurism at its most desirably perfect.