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