Public suffix domain
A domain under which independent organizations register their own names, such as com, org or co.uk; DMARC lets its operator publish a policy.
What it means
RFC 9989 calls these Public Suffix Domains and their operators Public Suffix Operators. A record at _dmarc.com never overrides a record that example.com publishes for itself, but a PSD operator can publish one with psd=y to set a default for registered names that publish nothing and to mark the organizational boundary.
The idea came from the experimental RFC 9091 and is now part of the standard.
There is nothing in a name that shows it is a public suffix; that has to come from DNS records or from lists such as the Public Suffix List.
Related terms
Sources
What this definition rests on. The wording is ours; the facts are theirs.
All 432 terms in the glossaryThe wiki: blocklists and bounce codes