The document defines cloud computing according to the National Institute of Standards and Technology (NIST). It identifies five essential characteristics of cloud computing (on-demand self-service, broad network access, resource pooling, rapid elasticity, and measured service). It also outlines three service models (Software as a Service, Platform as a Service, and Infrastructure as a Service) and four deployment models (private cloud, community cloud, public cloud, and hybrid cloud). The purpose is to provide a baseline definition and taxonomy to facilitate comparisons of cloud services and deployment strategies.