AAAA is a domain address record, that is in essence the IPv6 address of the web server where the domain is hosted. The IPv6 system was designed to replace the present IPv4 system in which each Internet protocol address is made up of 4 groups of decimal digits which range from 1 to 255 e.g. 18.104.22.168. In contrast, an IPv6 address has eight groups of 4 hexadecimal numbers - ranging from 0 to 9 and from A to F. The cause of this change is the significantly smaller selection of unique IPs that the existing system supports and the speedy increase of devices which are connected to the world wide web. An example of an IPv6 address would be 2101:1f34:32e2:2415:1365:4f2b:2553:1345. If you'd like to direct a domain to a machine which uses this type of an address, you'll have to create an AAAA record for it, and not the commonly used A record, which is an IPv4 address. The 2 records have the same exact function, yet different notations are used, so as to identify the two types of addresses.