Postback

I always see the term "postback" from ASP book, but I am not sure if I fully understand the meaning. Here's my understanding so far, please correct me if any mistakes. here's a typical html form:

<form action="process.asp" method="post">
'GUI code
</form>

"postback" action happens when the user click the submit button, that means it will invoke "process.asp" is the above code. In ASP.NET, if the web control has set AutoPostBack property to True, that means when there is any events on the web control, it will invoke "process.asp", just like the user click the submit button.