CentOS is short for Community Enterprise Operating System. This is one of the top Linux distributions for servers and it is regarded as one of the most reliable and secure 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 updating the code of all of them. It is also free to distribute and use, so you won't have to pay any kind of license fees, meaning that the overall price that you'll have 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 various other Linux distributions is its huge developer community, that will help you find the reply to any kind of question or problem you have. What's even more, each version which is released officially is supported for 10 years, that is is a lot longer than with any alternative OS. What this means is regular protection and stability updates that provides a great software environment for all of your web applications in the long run.