I need the correct definition for the word virus ...?

Answer 1

A computer virus is a computer program that can copy itself and infect a computer without permission or knowledge of the user. The original may modify the copies or the copies may modify themselves, as occurs in a metamorphic virus. A virus can only spread from one computer to another when its host is taken to the uninfected computer, for instance by a user sending it over a network or carrying it on a removable medium. Additionally, viruses can spread to other computers by infecting files on a network file system or a file system that is accessed by another computer. Viruses are sometimes confused with computer worms and Trojan horses. A worm, however, can spread itself to other computers without needing to be transferred as part of a host. A Trojan horse is a form of malware that presents itself as a legitimate program. In contrast to viruses, Trojan horses do not insert their code into other computer files. Many personal computers are now connected to the Internet and to local-area networks, facilitating their spread. Today's viruses may also take advantage of network services such as the World Wide Web, e-mail, and file sharing systems to spread, blurring the line between viruses and worms. Furthermore, some sources use an alternative terminology in which a virus is any form of self-replicating malware.

The term comes from the term virus in biology. A computer virus reproduces by making, possibly modified, copies of itself in the computer's memory, storage, or over a network. This is similar to the way a biological virus works.

Some viruses are programmed to damage the computer by damaging programs, deleting files, or reformatting the hard disk. Others are not designed to do any damage, but simply replicate themselves and perhaps make their presence known by presenting text, video, or audio, messages. Even these benign viruses can create problems for the computer user. They typically take up computer memory used by legitimate programs. As a result, they often cause erratic behavior and can result in system crashes. In addition, many viruses are bug-ridden, and these bugs may lead to system crashes and data loss.

There are many viruses operating in the general Internet today, and new ones are discovered every day.

Answer 2

Here's what Wikipedia says. This is the correct usage of the term, not the PC type:

A virus is a microscopic particle (ranging in size from 20 - 300 nm) that can infect the cells of a biological organism. Viruses can replicate themselves only by infecting a host cell. They therefore cannot reproduce on their own. At the most basic level, viruses consist of genetic material contained within a protective protein coat called a capsid. They infect a wide variety of organisms: both eukaryotes (animals, yeasts, fungi, and plants) and prokaryotes (bacteria and archaea). A virus that infects bacteria is known as a bacteriophage, often shortened to phage. The word virus comes from the Latin, virus, "poison" (syn. venenum).[1] The study of viruses is known as virology. Those who study viruses are known as virologists.

Answer 3

A Virus is a small program that embeds itself into other programs. When those other programs are executed, the Virus is also executed, and attempts to copy itself into more programs. In this way, it spreads in a manner similar to a biological virus

Virus can `infect' any executable code. Accordingly, they are found on floppy and hard disk boot sectors, executable programs, macro languages and executable electronic mail attachments

Answer 4

my understanding of the word is: a piece of malicious software
created with the intention to harm the operation of a computer. The harm can be manifested in several ways which range from mild to severe, in worst case it can render your system unusable