Ah, welcome to the fun that is trying to figure out exactly what Fedora is1?.
Fedora was a community project to build high-quality 3rd party RPMs for RedHatLinux. They packaged a lot of stuff that RedHat wouldn't, couldn't, or didn't. When Red Hat decided to become more community based to separate themselves from their commercial RedHatEnterpriseLinux distribution, they merged with the Fedora Linux Project to become the FedoraProject. The old Fedora Linux Project website 2? is is now the home of the FedoraExtras project.
Fedora is also a digital library framework, which preceeds the use of the name by RedHat. See http://www.fedora.info/redHat.shtml - (they are understandably unhappy with RedHat for using 'Fedora' as a trademark for computer-related fields).
And Fedora is the new name for what used to be FedoraCore. It is changing as of the 6 release.
[1] A Fedora is...
...a type of hat. This hat is a fedora.  This too is a fedora.  As is this.  You can even buy an official Red Hat Fedora. |
[2] They're cool for using a .us domain instead of an international one and then claiming that America == The World, like NetworkSolutions once did.
