Glossary and Definitions

Is a large distributed system of servers deployed in multiple data centers in the Internet.  The goal of a CDN is to serve content to quickly to end-users with high availability and high performance. CDNs serve a large fraction of the Internet content today.
An organization or commercial entity, accredited by both ICANN and generic top-level domain registry (gTLD) to sell gTLDs and/or by a country code top-level domain (ccTLD) registry to sell ccTLDs; to manage the reservation of Internet domain names in accordance with the guidelines of the designated domain name registries and to offer such services to the public.  Some common Domain Registrars are Go Daddy, NameCheap, Enom, and Network Solutions.
The process of purchasing and registering a domain name that in many cases, is used for a website. 
The DNS translates Internet domain and host names to IP addresses. DNS automatically converts the names we type in our Web browser address bar to the IP addresses of Web servers hosting those sites.
A logical address for a network adapter. The IP address uniquely identifies computers on a TCP/IP network.  IP addresses can be determined statically (assigned to a computer by a system administrator) or dynamically (assigned by another device on the network on demand).
Is one of the domains at the highest level in the hierarchical Domain Name System of the Internet.[1] The top-level domain names are installed in the root zone of the name space. For all domains in lower levels, it is the last part of the domain name, that is, the last label of afully qualified domain name. For example, in the domain name www.example.com, the top-level domain is .com (or .COM, as domain names are not case-sensitive). Management of most top-level domains is delegated to responsible organizations by the Internet Corporation for Assigned Names and Numbers (ICANN), which operates the Internet Assigned Numbers Authority (IANA) and is in charge of maintaining the DNS root zone.