The spread is the difference between the ASK price and the BID price. The BID price is the rate at which you can sell a currency pair, and the ASK price the rate at which you can buy a currency pair.
A continually growing glossary of Forex Terms. – ACCOUNT BALANCE: Amount of money in your account. APPRECIATION: A currency is said to appreciate when price rises in response to market demand; an increase in the value of an asset. ARBITRAGE: Taking advantage of countervailing prices