Derived from the name of Wei Dai, a cryptography pioneer, Gwei is a denomination of Ethereum, representing a fraction of one Ether, and is used to measure the cost of transactions or smart contract execution on the Ethereum network. 1 Ether (ETH) is equal to 1,000,000,000 Gwei.
Gas prices on the Ethereum network are typically denominated in Gwei. When users initiate transactions or execute smart contracts, they specify the gas price in Gwei to indicate how much they are willing to pay for each unit of gas used in the operation.
For example, if the gas price is 20 Gwei and a transaction requires 100,000 units of gas, the total cost of the transaction would be 0.0002 ETH (20 Gwei * 100,000 gas units = 0.0002 ETH).