Cloud computing is an umbrella term for elastic, on-demand, shared computing resources and services– such as computational power, storage capacity, database usage, analytics, and software applications– delivered as a service over the Internet, typically with metered pricing. The organizations that provide cloud computing are frequently referred to as cloud providers. See also the definitions of the three cloud-computing service models: IaaS, PaaS, and SaaS. For a formal definition and taxonomy of cloud computing, see the The NIST Definition of Cloud Computing, NIST Special Publication 800-145, at https://csrc.nist.gov/publications/detail/sp/800-145/final.