Top level domain is often referred to as TLD. It is defined as the last segment of a domain name. It can also refer to the part of a domain name that comes after the dot symbol. Top level domains are often broken down into two different categories. The first category is called generic TLDS. The other category is called country specific TLDS. Popular TLDS include dot com, dot org, dot net, and dot edu. Top level domains are the last segment of the domain name that comes after the dot symbol. Top level domains are at the top when it comes to domain names hierarchy.