DNS record
One entry in DNS: an owner name, a type such as A, MX or TXT, a class, a TTL and the data, published in a domain's zone.
What it means
RFC 1035 calls a DNS record a resource record (RR). Each has an owner name (example.com or _dmarc.example.com), a type, a class (almost always IN, for internet), a TTL in seconds, and type-specific data. All records with the same name and type form a set returned together.
Mail uses a handful of types: MX for routing, A and AAAA for server addresses, TXT for SPF, DKIM, DMARC, MTA-STS and verification tokens, CNAME for provider-managed DKIM keys, PTR for reverse DNS, and TLSA for DANE. IANA keeps the registry of all record types.
Records are edited at the DNS host for the domain, which is not always the registrar.
Example
example.com. 3600 IN MX 10 mx1.example.com.Related terms
On this site
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