From Cool Hand Luke: "
What we have here is a failure to communicate." :)
Email exists on mail servers that serve a domain identified by what follows the "@" sign in an email address. These mail servers are provided by many entities, e.g. ISPs, web hosting services, any individual with a computer, and the list goes on. All mail servers have basically the same functions:
- Maintain accounts for email users
- Administer usernames and passwords for email accounts in its domain.
- Receive emails destined for its domain
- Upon request and authentication from an email client (username/password, allow access to emails for that user, and optionally allow deletions of emails belonging to that user.
- There are other server functions related to sending emails not related to this discussion.
What an email client (vs the email server) does with this access to an email account is up to that client but basically all a client can do is access emails on the server and (optionally) delete emails on the server.
And that is where all the confusion begins. Early on email clients were device based but as technology evolved that model became limiting as users wanted access to their email from many different devices and locations. Hence web-based email clients that could access a email server from any device in any location.
Google uses "Gmail" to refer to two different things that adds to the confusion. Their mail server(s) that serve their domain (gmail.com) and their Gmail client(s) on devices or a website that can access email on a gmail server or any other email server out there in the universe. And contrary to a comment in another post, a Gmail client app on a phone/tablet has the same function as a browser based Gmail client. After all Gmail clients are synced such that any user configuration change made on one client is reflected in all Gmail clients of that user. In any case they just access emails on mail servers.
Here's a link that is more inclusive than my feeble attempt above:
Email Explained