What is Cloud. And what are IaaS, PaaS, and SaaS?

The word " Cloud " is getting more heard and used with days passing by. So what actually is a Cloud (or) a Cloud platform (or) Cloud computing (or) Cloud services. Basically these are platform, computing ability, services respectively which are hosted in some part of the world and are accessible over Internet . To understand the best, we can take an example like electricity. In general, You just use electricity as an utility and pay according to the usage. You would seldom have to build, maintain and generate your own electricity - because of the comfort you receive using electricity as an utility. Cloud services can be mapped to the same concept. Cloud computing services can be of three kinds, private , public and hybrid . And they act as the name suggests. Many articles can be found in the internet on the definitions, pros and cons. Three such major cloud service providers are: Microsoft Azure - https://azure.microsoft.com/en-us/ Amazon web services - https:/...