A faint second image that appears close to the primary image on a CRT. A CRT ghost is an electronics synchronization problem.
A faint second image that appears close to the primary image on a printout from a mechanical printer. It is caused by bouncing print elements as the paper passes by.
A double image appearing in 3D shutter glasses due to synchronization issues. See 3D sync
To make an exact copy of an operating system or the contents of a hard disk for backup or for migrating to another computer. Aptly named, Norton Ghost is a popular utility that duplicates the contents of a hard drive. The program can also be used to copy failing disks, taking hours to complete the operation, because it has to re-read marginal sectors over and over. See ghosting server
and cloning software
A secondary signal in a communications transmission that arrives ahead of or later than the primary signal.