RHEL stands for Red Hat Enterprise Linux, an open source Linux distribution that is based on free, open source code.
One of the purposes of RHEL is to support workloads in virtualised and physical environments.
Initially released in 2000, under the name Red Hat Linux Advanced Server, it is based on free, open source code which has been made available for download. However, direct copying of the code is not allowed.
The distribution is aimed at the enterprise market.