Gíga-wei; a denomination of ether (ETH), the traditional currency of the Ethereum network.
Gwei is a division standard or denomination of Ethereum’s cryptocurrency, ether (ETH). Specifically, it is equivalent to 1 billionth of an ether, meaning that 1 billion Gweis make up 1 ETH. It is the middle denomination in the ether hierarchy, so it is correspondingly greater than Wei, Kwei, and Mwei, but less than Microether, Milliether, and Ether. Nevertheless, it is one of the most common ETH denominations used as gas (transaction fees) on the Ethereum blockchain.
A Gwei is to ETH what a satoshi is to Bitcoin (BTC). It is also referred to as nanoether.