In the DNS we might need more than one host serving a particular type of service, for example "Google" would not only have a single machine serving all its requests. It might have 10 or 20 machines serving requests for searchers.

So how does that work, how would we have 20 machines all pointing to the same name?

They must all surely be known as www.google.com even though there are 20 different physical machines behind that name. One of the ways that they do this is to round robin DNS where DNS offers an IP address in a round robin fashion. (Offering a DNS service to machine number 1 through 20 and then back to 1 again, to start the cycle again.)