Cloud computing, method of running application and storing related data in central computer systems and providing customers or other users access to them through the internet.
Origin of Cloud Computing:
The origin of the expression cloud computing is obscure, but it appears to derive from the practice of using drawings of stylized clouds to denote networks in diagrams of computing and communications systems. The term came into popular use in 2008, though the practice of providing remote access to computing functions through networks dates back to the mainframe time sharing systems of the 1960s and 1970s.
In simple terms, Hadoop can be used to distribute cloud computing services i.e. It is a distributed platforms.
You can assume cloud computing to be a concept or methodology, which Hadoop is not. Hadoop itself is based on the methodology of Distributed computing. It’s like asking, what’s the difference between programming and Java. Programming is something which can be done through Java but definitely Java, all by itself, is not programming. Same holds true in case of Hadoop and cloud computing.