A computer program that can reproduce by changing other programs to include a copy of itself. It is a parasite program, needing another program to survive. (Eth, Gr. 8)
A computer program that is designed to replicate itself by copying itself into the other programs stored in a computer. It may be benign or have a negative effect, such as causing a program to operate incorrectly or corrupting a computer's memory.
A malevolent program that becomes embedded in a computer system or application. Viruses are most commonly transmitted through e-mail. Recently strains have appeared that use personal e-mail address books to propagate themselves from machine to machine.