CentOS is an abbreviation for Community Enterprise Operating System. This is one of the top Linux releases for servers and it's recognized as being one of the most reliable and safe Operating Systems out there. CentOS is open-source software, which means that you're able to customize it in whatever way you see fit, adding and removing packages or changing the code of all of them. It is also free to distribute and use, so you won't need to pay any kind of license fees, which means that the overall price that you will have to pay for a server making use of CentOS will be cheaper as compared to the price for a server running an alternative OS. What makes CentOS unique among other Linux distributions is its huge developer society, which will help you find the answer to any kind of question or problem you may have. Furthermore, each version that's released officially is supported for a decade, that is is longer than with any other OS. What this means is frequent security and stability updates which will provide a stable software environment for all of your web applications in the long run.