Bancor Network is a protocol that is based on built-in price discovery and mechanism of liquidity for cryptocurrencies on smart blockchains. In a more basic way explaining, it is primarily a platform for smart token creation and exchange of those tokens. Tokens created in the network are backed by Bancor’s own token called BNT. The BNT reserve supplies a strong liquidity for trading the tokens. Next to smart tokens, it is also possible to trade other Ethereum tokens within the platform using smart contracts.
(http://blog.bancorprice.org/bancor-network-an-introduction/)