AAAA is a domain name record, which is essentially the IPv6 address of the web server in which the domain is hosted. The IPv6 system was intended to replace the current IPv4 system where every single Internet protocol address consists of four sets of decimal numbers between 1 to 255 e.g. 220.127.116.11. However, an IPv6 address features 8 groups of 4 hexadecimal digits - which range from 0 to 9 and from A to F. The main reason for this change is the considerably smaller range of unique IPs that the existing system supports and the rapid increase of products that are connected to the world wide web. A good example of an IPv6 address would be 2101:1f34:32e2:2415:1365:4f2b:2553:1345. If you wish to point a domain to a server that uses this sort of an address, you have to set up an AAAA record for it, not the commonly used A record, which is an IPv4 address. The 2 records have the same exact function, yet different notations are used, in order to distinguish the two forms of addresses.