Cloud Computing has had a multiplicity of definitions but essentially a means by which organisations or individual users can access computer services or data, even though that data is not stored within that organisation but elsewhere. We’re used to cloud computing services such as Gmail, You Tube, Facebook and Twitter, even though we may not use such terminology, an indication of the differing types of cloud services.
The nearest thing to a standard definition is the one from the US National Institute of Standards and Technology in which cloud is defined as “a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (for example, networks, servers, storage, applications and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction”.