CCI (Commodity Channel Index): A cyclical technical indicator that is often used to detect overbought/oversold states of the market.
CFD: A Contract for Difference — special trading instrument that allows financial speculation on stocks, commodities and other instruments without actually buying.
CPI: Consumer price index the statistical measure of inflation based upon changes of prices of a specified set of goods.
ECN Broker: A type of Forex brokerage firm that provide its clients direct access to other Forex market participants. ECN brokers don't discourage scalping, don't trade against the client, don't charge spread (low spread is defined by current market prices) but charge commissions for every order.