Yup! Those websites are the instances which are the infrastructure and interface by which you can access communities - each of which is hosted on a specific instance. An instance is essentially the collection of all the communities it hosts and all of the users signed up through that instance.
Oh, got ya! What about different links for lemmy? For example, the ones that end in .ee or .ml? Are those instances?
Yup! Those websites are the instances which are the infrastructure and interface by which you can access communities - each of which is hosted on a specific instance. An instance is essentially the collection of all the communities it hosts and all of the users signed up through that instance.