Gwei is denoted in the Ethereum cryptocurrency (ETH) and is used on the Ethereum network. This Ethereum is also a blockchain platform just like Bitcoin where users can transact among themselves to purchase and sell goods & services without intermediaries or third-party intervention.
Gwei is also called nanoester or simply nano to denote the ninth power of fractional ETH. If you try to imagine the physical size of gwei – how you can visualize 100 pennies – you probably won’t be able to because measurements on the air are almost invisible, like digital dust.