(1) See ghosted.

(2) A faint second image that appears close to the primary image on a CRT or printout. A CRT ghost is an electronics synchronization problem. A printer ghost is caused by bouncing print elements as the paper passes by.

(3) To make an exact copy of an operating system or the complete contents of a hard disk either for backup or migrating from one computer to another. Aptly named, Norton Ghost is a popular software utility from Symantec that is widely used to copy the contents of a hard drive from an existing PC to a new one. It can also be used to copy disks that are failing, even taking 24 hours or more to complete the operation because it has to read and re-read marginal sectors from the old disk. See ghosting server.

(4) In a transmission, a secondary signal that arrives ahead of or later than the primary signal.