What's the difference between a web site and a web app?

Question

I know, it's maybe a rather popular question, and I wasn't banned in Google by the way.

I need to write a project work for Uni, it will be some calculations of civil engineering (in short: automation calculation in web, not desktop).

In some places says that difference between a web app and a web site in interaction, in others - that in a compilation. I can't get it. Is logic on the client part/server part makes a difference? Maybe you can give me some examples?

Answer 1

Web app = A dynamic web site with an interactive element for the user.