CentOS is short for Community Enterprise OS. This is one of the best Linux releases for servers and it's well known as being one of the most stable and risk-free Operating Systems available. CentOS is open-source software, so you are able to customize it in whatever way you see fit, adding and removing packages or changing the program code of all of them. It is also free to distribute and use, so you won't need to pay any license fees, meaning that the total price that you'll need to pay for a server running CentOS will be cheaper than the price for a server running some other OS. What makes CentOS unique among other Linux releases is its huge developer society, which will help you get the answer to any kind of question or problem you might have. What's even more, each version which is released officially is supported for 10 years, that is is much longer than with any alternative OS. This means regular security and stability updates which provides a great software environment for all of your web applications in the long run.