@steveb a good analogy that non combatants can understand is mobile phones, the number is the domain name, the physical phone is the site and the provider is the host.
You can move the number (domain name) from provider (host) to provider (host) and it can be pointed at different phones(sites).
Another analogy can be used for DNS, you can give someone the lat/long (ip address) of a location but it’s far easier to give them a street address (domain name). The relationship between lat/long and a street address is a map, the relationship between an IP address and domain name is a/the DNS.
For everyone to be able to find a specific street address it needs to be marked on lots of maps, for everyone to be able to find an iP address (site) it’s domain name needs to be listed/propagated across lots of DNS servers.