To help you think about the concepts we employ…
The World Wide Web is a World Wide Town
Your computer is like an assistance dog, trained to run and fetch things for you to look at.
Your website is your collection of belongings and furniture and appliances.
Your webhost is your landlord.
Your server, where your website resides, is like the house or apartment you rent.
The mail server is an old-fashioned post office.
The DNS, or domain Name server (or nameserver) is the town gossip, who knows everything about everybody., and specifically is able to give directions to your house to strangers in town.
A domain Name is your unique name (joansmith.com, mybusiness.net)
Your IP address is the street address where your house is built.