In the forex, market spread means the difference between the bid and ask price. This value changes per second as the fluctuation of price is the main fundament of the forex market.
Spread is basically the exchange rate of the currency pair, in which the base currency is shown on the left of the currency pair, and the quote currency is shown on the right side of the currency pair. The pairing illustrates how much of the quote currency or variable currency equals one unit of the base currency.