Part of Domain Name

A domain name usually consists of two or more parts (technically labels), separated by dots. For example example.com.

The rightmost label conveys the top-level domain (for example, the address www.example.com has the top-level domain com). Each label to the left specifies a subdivision, or subdomain of the domain above it. Note;"subdomain" expresses relative dependence, not absolute dependence. For example: example.com comprises a subdomain of the com domain, and www.example.com comprises a subdomain of the domain example.com. In theory, this subdivision can go down to 127 levels deep. Each label can contain up to 63 characters. The whole domain name does not exceed a total length of 255 characters. In practice, some domain registries may have shorter limits. A hostname refers to a domain name that has one or more associated IP addresses; ie: the www.example.com and example.com domains are both hostnames, however, the com domain is not.