A Whitelist is a list of things that are not banned or blocked.
For example Ad Blockers generally do not block all ads. Some only block ads which are malicious or annoying, and some let advertisers pay to not block their ads. The advertisers who have ads that can get through an Ad Blocker are referred to as being “Whitelisted”.
Similarly, sometimes people send emails which look like spam, but which are not actually spam. If you whitelist the sender of those emails, it means they won’t get blocked by your spam filter.Glossary Index