A sprite is a graphical object that is specified once, then animated by making calls to special QuickTime routines. Most other animation techniques are based on bitmaps or vectors that must be constantly redefined.
Sprites consume much less memory because they are defined only once.
A QuickTime sprite is a freestanding animated graphic. If the user's screen is like a stage, sprites are like actors that can show up anywhere, move around, and change form. The advantage of sprites is that they are easy to control and don't use much memory. You define each sprite once and then animate it with simple commands, instead of defining dozens of byte-gobbling bitmaps, one for each location. In QuickTime, sprites are defined by means of QT atoms.