Example: "You should run an antivirus program to make sure your computer isn't infected."
Antivirus (also written "anti-virus" or simply "AV") is software designed to prevent, detect, and remove viruses from a computer. Once installed, most antivirus programs run in the background, scanning new files for viruses and performing regular system checks. You can also use an antivirus utility to scan individual files or folders directly. The software operates by checking files against a database of virus definitions, which contain signatures of known viruses. If a file contains a virus, the antivirus program will typically quarantine the file, making it inaccessible (and therefore removing the threat). It may also mark the file for deletion.
While antivirus software primarily scans for viruses, most modern antivirus programs also scan for other types of malware. This includes trojan horses, worms, spyware, and adware. Many antivirus programs are now included as part of "internet security" suites, which offer additional types of system protection, such as customizable firewalls, website blocking, and port monitoring.
Updated: August 21, 2013