A definition of the computer virus

I have to state that this to me is a bare minimum answer for the this term, and is not totally correct. I am a IT Sec student, so we have been given many technical definitions. The term virus is more of a blanket term now, much like malware. But please read this and look up the site through the link.

"A virus is a simple program designed to cause harm to someone else's computer. A virus spreads by duplicating and attaching itself to other files. The extent of the damage depends on the virus. There are tens of thousands of viruses.
Some virus damage is insignificant but inconvenient. Some virus damage is disastrous, putting the computer system out of action by erasing files or corrupting data."

http://www.bbc.co.uk/schools/gcsebitesize/ict/implications/virusesrev1.shtml