AAAA is a domain address record, that's essentially the IPv6 address of the server in which the domain is hosted. The IPv6 system was intended to replace the existing IPv4 system where each and every IP consists of four groups of decimal digits between 1 to 255 e.g. 126.96.36.199. In contrast, an IPv6 address has eight groups of four hexadecimal numbers - ranging from 0 to 9 and from A to F. The cause of this modification is the considerably smaller number of unique IPs that the current system supports and the rapid increase of gadgets which are connected to the world wide web. An example of an IPv6 address is 2101:1f34:32e2:2415:1365:4f2b:2553:1345. If you need to point a domain to a machine that uses this kind of an address, you have to create an AAAA record for it, not the commonly used A record, that is an IPv4 address. Both records provide the same exact function, yet different notations are used, so as to separate the two forms of addresses.