The Ethereum network is a decentralized software platform that allows the creation of smart contracts and decentralized applications running on blockchain technology. Ether is a cryptocurrency that fuels the Ethereum network.
There are a few different types of Ethereum units. The most well-known is Ether, the currency used to pay for things on the Ethereum network. In addition to Ether, there are also two other unit types: Gas and Wei.
Gas is used to measure how much work action or transaction on the Ethereum network costs. Transactions that require more Gas will be processed sooner than those that require less Gas. The price of gas is set by the market and varies depending on network congestion and other factors.
Wei is the smallest unit of Ether and is equivalent to one hundred millionth of a single Ether. Wei is used to measuring too small transactions to be worth using Ether as a denomination. For example, if you wanted to send someone 0.001 ETH, you would send them 10,000 Wei instead.