A business which facilitates cryptocurrency trading. Some deal with only crypto-crypto pairings while others support crypto-fiat pairings as well.
Crypto-crypto exchanges only exchange between cryptocurrency pairs. Since they avoid dealing with fiat currencies, their requirements are often a bit less strict to register, and often support a larger amount of low market-cap and emerging coins.
Crypto-fiat exchanges allow exchange between crypto and fiat pairs. These exchanges usually require some KYC checks before trading is allowed, and are the most common way to purchase and sell cryptocurrencies.
* All terms and definitions may update as the Cryptionary improves.