what does it mean for a cloud system to be elastic

In cloud computing, elasticity refers to the ability of a cloud system to adapt to workload changes by provisioning and de-provisioning resources in an autonomic manner, such that at each point in time the available resources match the current demand as closely as possible. Elasticity is a defining characteristic that differentiates cloud computing from previously proposed computing paradigms, such as grid computing. Elastic computing is the dynamic adaptation of capacity, e.g., by altering the use of computing resources, to meet a varying workload. Elasticity enables organizations to rapidly scale capacity up or down, either automatically or manually, to meet changing demands without worrying about capacity planning and engineering for peak usage. In other words, elasticity allows a cloud system to grow or shrink capacity for CPU, memory, and storage resources to adapt to the changing demands of an organization. Without elasticity, organizations would have to pay for capacity that remained unused for most of the time, as well as manage and maintain that capacity with OS upgrades, patches, and component failures.