IP address
An Internet Protocol address (IP address) is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication.
An IP address serves two principal functions: host or network interface identification and location addressing.
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DNS stands for "Domain Name System." The domain name system acts like a large telephone directory and in that it's the master database, which associates a domain name such as "www.wikipedia.org" with the appropriate IP number. Consider the IP number something similar to a phone number: When someone calls www.wikipedia.org, the ISP looks at the DNS server, and asks "how do I contact www.wikipedia.org?" The DNS server responds, for example, "it can be found at: 216.198.221.66.". As the Internet understands it, this can be considered the phone number for the server that houses the website. When the domain name is registered/purchased on a particular registrar's "name server", the DNS settings are kept on their server, and in most cases point the domain to the Name Server of your hosting provider. This Name Server is where the IP number (currently associated with your domain name) resides.