AAAA is a domain record, that is in essence the IPv6 address of the web server in which the domain is hosted. The IPv6 system was designed to replace the existing IPv4 system where each and every IP consists of 4 groups of decimal digits ranging from 1 to 255 e.g. 184.108.40.206. On the other hand, an IPv6 address has eight groups of four hexadecimal digits - from 0 to 9 and from A to F. The reason for this modification is the considerably smaller selection of unique IPs the current system supports and the rapid increase of devices which are connected to the Internet. A good example of an IPv6 address is 2101:1f34:32e2:2415:1365:4f2b:2553:1345. If you need to point a domain to a server that uses this sort of an address, you have to set up an AAAA record for it, and not the commonly used A record, that is an IPv4 address. Both records provide the very same function, but different notations are used, to identify the two forms of addresses.