What is Ethereum and how is it different from Bitcoin?
The first thing to know is that cryptocurrencies like Bitcoin or Ethereum are one of the many applications that are supported by blockchain technology, in the same way that email is only one of the many applications of the internet. Essentially a distributed public blockchain network that runs the programming code of decentralised applications (Dapps), Ethereum goes beyond being a cryptocurrency in terms of both purpose and ability.
Bitcoin is a decentralised application that creates a P2P cash system, wherein users can transact in bitcoins. On the other hand, Ethereum allows developers to build and launch decentralised applications for any purpose of theirs, including creating their own cryptocurrencies. By distributing the processing power required to run these programmes between peers on the network, Ethereum essentially acts as a blockchain supercomputer. Moreover, due to the principle of consensus, apps on the network run exactly as programmed without any possibility of censorship, downtime, fraud, or third-party interference.
Source : https://yourstory.com/2017/12/laymans-guide-to-ethereum/amp/