Definitions of cloud computing are easy to find, but a single, authoritative definition is hard to come by. Perhaps the best work in this area was done by Böhm, et al. By compiling characteristics of 17 different scholarly and industrial definitions, the authors identified five primary characteristics of cloud computing allowing a definition such as: “Cloud computing is a service that delivers scalable hardware and/or software solutions via the Internet or other network on a pay-per-usage basis.” (Emphasis indicates essential definition elements).
Cloud computing can further be broken down into three common types: SaaS, PaaS, and IaaS. SaaS (Software as a Service) allows users to log into and utilize preprogrammed software that is owned and maintained by the service provider. PaaS (Platform as a Service) gives users tools and languages owned and maintained by the service provider that can be used to build and deploy customized applications. IaaS (Infrastructure as a Service) provides users with storage and processing, allowing users full control over the use of that infrastructure. There are other divisions of cloud computing, but these are the most common.