In side Route 53:
[your domain] --- mapped to ---> [Name servers] --- set by---> [Hostzone]
Here are the rules:
1, Domain is globally unique, you register it and need to pay for it. (around $15/year)
Once you registered, it is located in Amazon's route 53. Which means those root, top DNS servers don't record your domain. When request comes, they refer to Amazon's server to give the answer.
2, Amazon uses Name servers to resolve the request. This means if you have a domain but no related name server, it still won't be resolved.
You can create a name server by creating host zone.
3, Each public host zone have multiple unique name servers created along the host zone.
So creating records in host zone will also update those record to name servers.
record is the rule for translating domain name to ip address.
Private hostzone have same name server and it is only attached to a VPC for instances inside the VPC
So, actually you can create a record in your host zone resolving google.com to your own server. But actually, this domain name is associated to other true name server, so your host zone won't have effect. If google really uses your name server, then the resolve will base on your settings.
Also, maintain the hostzone also cost you some money.