Blacklist
List of known bad (malicious) sites, servers or programs
A blacklist is a list of websites, email servers or files that are known to be 'bad'. Website filters use such lists to block sites hosting malicious or otherwise unwanted content, spam filters use them to block mails from mail servers that are known to send spam, and security software uses them to block malicious applications from running.
Blacklisting is often used in conjunction with whitelisting, sometimes with the unknown items in between forming a 'greylist'.
