Ethereum is a decentralized platform that runs smart contracts: applications that run exactly as programmed without any possibility of fraud or third party interference.
In order to run these applications, Ethereum uses a virtual machine called the Ethereum Virtual Machine (EVM), which can execute code of arbitrary algorithmic complexity.
In order to achieve this, Ethereum borrows heavily from Bitcoin’s design, but also has its own unique features. For example, Ethereum has a slightly different economic model than Bitcoin – rather than having a limited supply, Ethereum has a variable supply that increases over time (this is known as “inflation”).
This is because new Ether is created every time a block is mined (a block is mined every 15 seconds on average).
Ether is the native cryptocurrency of the Ethereum platform and it is used to pay for transaction fees and gas. Gas is a unit of measurement that denotes the amount of computational effort that is required to execute a particular operation or program on the Ethereum network.
The denomination used in Ethereum is ETH.