Peter Mell & Tim Gance, The NIST Definition of Cloud Computing (Final) (NIST Special Publication 800-145) (Sept. 2011) (full-text).
|“||describes how cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction.||”|
NIST intends the definition "to serve as a means for broad comparisons of cloud services and deployment strategies, and to provide a baseline for discussion from what is cloud computing to how to best use cloud computing." Cloud computing is still an evolving paradigm. Its definition, use cases, underlying technologies, issues, risks, and benefits will be refined and better understood with a spirited debate by the public and private sectors. This definition, its attributes, characteristics, and underlying rationale will evolve over time.