Web, domains and email
ARC
Abbreviation for Authenticated Received Chain
In short and in plain language
ARC is a method for mail servers.
When they forward an email, they note the results of its checks. Then the person who gets it can see that it was real on its way.
This works even if it went through mailing lists or was passed on. The method adds to other checks for email.
Definition
ARC is a method by which mail servers record the results of email checks when forwarding messages. This lets the recipient see that a message was genuine on its way, even if it passed through mailing lists or forwarding. It complements SPF, DKIM and DMARC.