Any currency transaction involves a currency pair, one currency is bought and another is sold.
The rate at which a currency is bought is known as Bid Rate, while the rate at which it is sold, is known as Ask Rate
There are two different quotations of currencies: Direct Quote is the number of units domestic currencies required to buy a unit of foreign currency. Indirect Quote is the number of units of foreign currency required to buy a unit of domestic currency.
Read the full article: Quick guide on basics of Currency Transactions