A worm may refer to any of the following:
1. First developed by John Shoch and Jon Hupp at Xerox PARC in 1978, a worm is a destructive self replicating program containing code capable of gaining access to computers or networks. Once in the computer or network, the worm causes harm by deleting, modifying, distributing, or otherwise manipulating data.
2. Short for Write Once Read Many, WORM is a CD technology first introduced by Philips and Sony in 1988 that can be written to once and then read from after that multiple times. See CD-R for additional information.