computer virus

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun computing A program which can covertly transmit itself between computers via networks (especially the Internet) or removable storage such as CDs, USB drives, floppy disks, etc., often causing damage to systems and data.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a software program capable of reproducing itself and usually capable of causing great harm to files or other programs on the same computer