'cloud' is a virtual concept where the sharing of servers for storage or computing can be done avoiding the physical component usage
Clouds are basically visible bodies of very fine water droplets or ice particles or we can say it is a mass like a dust, smoke or steam that is suspended in the outer space. Clouds are produced by the condensation of water vapor (the ordinary atmospheric cloud). Other clouds, less commonly seen, are composed of smoke. Normally Clouds are formed when air containing water vapor is cooled below a critical temperature called as dew point and the resulting moisture condenses into droplets on microscopic dust particles in the atmosphere.
The World Meteorological Organization (WMO) uses a classification which divides clouds into 3 main levels: low-level, middle-level and high-level forms within the middle latitudes. A shallow layer of cloud at or near ground level is known as fog.