CentOS is short for Community Enterprise OS. This is one of the best Linux distributions for servers and it's well known as one of the most stable and protected Operating Systems on the market. 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 updating the program code of all of them. It's also free to distribute and use, so you won't have to pay any license fees, which means that the overall price that you'll have to pay for a server making use of CentOS will be much lower than 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 reply to any question or problem you may have. In addition, each version that's released officially is supported for 10 years, that's is longer than with any alternative operating system. This means routine security and stability updates which will provide a great software setting for your web apps in the long run.