The base currency is EOS; the counter currency is USD. In the EOS/USD pair a traditional (fiat) currency - the American dollar - is quoted against a cryptocurrency - EOS. Unlike USD EOS is a decentralised currency. Like other cryptocurrencies it works using a blockchain-based operating system which is able to process over 100000 transactions per second. The EOS platform was established by a company called block.one. Catch up on the recent EOS/USD rate by following the EOS/USD charts at Capital.com.