A bauble was originally a stick with a weight attached, used in weighing a child's toy, but especially the mock symbol of office carried by a court jester. This was a baton terminating in a figure of Folly with cap and bells, and sometimes having a bladder fastened to the other end. Subsequently it became a term for any triviality or childish folly.
More recently the term means a virtually worthless decorative object. It has particular application to a Christmas ornament.