Ethereum cryptocurrency and tokens

Ether is Ethereum's native cryptocurrency. In other words, ether to Ethereum is like BTC to bitcoin. Due to the forking for handling a hacking event in 2016, two competing Ethereum coins were generated, and both are currently traded at cryptocurrency markets. Their symbols are Ethereum (ETH) and Ethereum Classic (ETC). ETH is priced a lot higher than ETC.

Unlike BTC (that has only one denomination but can be divided into fractions), ether has many denominations. An ether is the biggest unit. The smallest unit is a Wei, named after a digital money pioneer, Wei Dai. Wei invented B-money. Other units include a Gwei, microether, and milliether. They are known by other names as well. For example, a milliether is also called Finney, named after another digital money pioneer, Harold Thomas Finney II, who in 2004 implemented the world's first cryptocurrency, reusable proofs of work (RPOW) before bitcoin. The following table lists conversion rates between ether and other units:

In addition to the native cryptocurrency, Ethereum allows users to issue their tokens. The issuance of a customized token needs to follow predefined technical standards. One well-known standard is the ERC-20 token. ERC refers to Ethereum Request for Comment, and 20 is the number assigned to the request. ERC-20 standard defines a list of rules for issuing ERC-20 tokens. By doing so, it allows for interaction and conversion among Ethereum tokens, and also with Ether. There are many other standards, for example, ERC-223, ERC-721, and so on.