Interbank Market

What Does Interbank Market Mean?
The financial system and trading of currencies among banks and financial institutions, excluding retail investors and smaller trading parties. While some interbank trading is performed by banks on behalf of large customers, most interbank trading takes place from the banks' own accounts.

Investopedia explains Interbank Market
The interbank market for forex serves commercial turnover of currency investments as well as a large amount of speculative, short-term currency trading. According to data compiled in 2004 by the Bank for International Settlements, approximately 50% of all forex transactions are strictly interbank trades.