Gwei is a subunit of the Ether (ETH) cryptocurrency on the Ethereum network. A gwei, also known as a gigawei, is the smallest base unit of Ether. It is 1,000,000,000 wei. One gwei is equivalent to 0.000000001 ETH (10-9). In contrast, 1 ETH equals 1 billion gwei.
Gwei is a handy way to quantify gas fees (amounts charged to miners for transaction processing). Ethereum sub-units sometimes also have nicknames, like in this case Gwei’s nickname is “shannon,” after Claude Shannon, the mathematician, and cryptographer known as “the founder of knowledge theory.”
See all ether units here.