Offer – The offer price is another name for the ask price, the rate at which a trader may buy a currency.

Offsetting Transaction – An offsetting transaction is an open position that partially or fully cancels out the value of another open position.

One Cancels the Other (OCO) – A two-part order whereby execution of one part automatically cancels the other part.

Open Order – Open orders are contracts that do not execute as a transaction until a designated price or time is met. Most open orders are GTC orders.

Open Position – An open position is any trade that has been entered but is not yet offset by an opposing trade. The position remains open until an offsetting transaction closes it.

Over-the-Counter – An OTC transaction is any trade that is not conducted through a centralised market, such as a stock market. All foreign currency exchanges are over-the-counter.

Overbought – When demand for a currency pushes the price to rise by over 150 percent of its average movement it is said to be overbought. Overbought currencies usually drop again by a similar amount.

Oversold – When demand for a currency causes the price to drop by more than 150 percent its usual movement, it is oversold. Oversold currencies soon rise in price to their usual range.

Overnight Position – An overnight position is a trade that remains open through the close of a business day.

Order – A trader’s instructions to a broker or dealer to execute a transaction under the specified conditions.