I get it... website stuff is confusing, especially if you've never really experienced it before!
In an effort to REALLY make it simple, take a look at the illustration below!
Domain Names = eg: www.magicfingers.co.nz Your address on the internet.
Hosting = Kind of like a house section, which gives a place to your address. You pay this regularly like power bills or rates.
Website Build/ Development = Like laying the foundation, the framing and creation of a house.
Website Design/Usability = Making the interior and exterior look good, and work in a user-friendly way. Like adding footpaths to garden, painting the walls and decorating.
Email = A mailbox to put all those digital letters in.
Put this all together and you have a website that works!