What is a cms frontpage theme?

What are CMS frontpage themes, like Dixi, Nelo, and Triden? Are they static front pages that emphasize images and widgets rather than blog posts? If so how are other pages treated? Is the header and footer defined by the theme on other pages? Or does the theme only create a front page? I know what CMS means (content management system) but I'm hung up on the term "frontpage." (P.S. before posting, I looked in the theme documentation, forums, your manuals, and google).