Definition: A firewall is a security measure designed to keep unauthorized computers, users, and networks from accessing data on another computer or network. Firewalls are especially important to Web searchers since they can potentially protect the user from malicious spyware, viruses, and hackers encountered while online.
Related: What is a Virus?
More about Firewalls
Also Known As: firewall software, firewall hardware, network firewall
Alternate Spellings: Fire Wall