A whitelist in emailing refers to a list of approved email addresses or domains that are allowed to send messages to a particular recipient. This list acts as a filter, allowing only emails from trusted sources to reach the recipient’s inbox while blocking all others. This helps to prevent spam, phishing, and other malicious emails from reaching the recipient’s inbox. Whitelisting is often used by individuals and businesses to ensure that important emails are not accidentally marked as spam and to maintain a secure and organized inbox.