In a nutshell, the Domain Name System (referred to as DNS) translates human readable domain names into IP addresses.
Most of the time, your computer will contact your Internet Service Provider's DNS server and receive the IP address for the website you want to load.DNS propagation is also used sometimes to describe the time taken for Internet Service Providers to update their own local DNS caches, since some Internet Service Providers do not always update their local cache based on the TTL of authoritative name servers. This is a numerical address assigned to computers and servers on the Internet. Computers need to have an IP address in order to find and communicate with each other over the Internet.Hostname: A name or label that has been assigned to a host computer.This will prevent you from being able to load a website if the server IP address changes in the future, until you remove or edit the entry in the hosts file. The lower the priority number, the higher the priority (yes, it sounds a little backwards).
MX (Mail Exchange) record: A MX record specifies where email should be delivered. Some mail systems have different MX records for different inbound servers.
This term is generally used to describe the time taken for the cache of TLD name servers to be updated after changes are made to a domain name's authoritative name servers.