Wei
Candlefocus EditorWei is used to facilitate transactions on the Ethereum network and to store balances. A single wei is too small to be useful for day to day transactions, and so transactions are usually represented in units of ether, or “ether”, which is equal to one millionth (1/1,000,000) of an ether.
The use of wei ensures that Ethereum transactions can be made with any denomination, providing a similar degree of flexibility to the Bitcoin protocol's use of satoshi as its smallest unit of currency. It also helps keep fees charged by the network low, since it creates an opportunity to save on fees.
The use of wei is likely here to stay, as it is an important part of the Ethereum protocol and helps ensure that even tiny transactions can be made over the network. As more Ethereum users come online, wei will become increasingly important as the underlying unit of the Ethereum network, facilitating the growth and development of the Ethereum ecosystem.