CentOS 7 is a distribution built by compiling the source code for Red Hat Enterprise Linux 7.This is the first release for CentOS 7 and is version marked as 7.0-1406. Since the upstream EL7 release, there have been some updates released - these have been built and are being pushed to the CentOS mirror network at the moment.
About CentOS
CentOS as a group is a community of open source contributors and users. Typical CentOS users are organisations and individuals that do not need strong commercial support in order to achieve successful operation. CentOS is 100% compatible rebuild of the Red Hat Enterprise Linux, in full compliance with Red Hat's redistribution requirements. CentOS is for people who need an enterprise class operating system stability without the cost of certification and support.