what a gap meant in forex is a situation when the market price closes at say 1.3458 on friday ,then on Monday morning,instead of the market opening with the closing price of 1.3458 on Friday,the price has increased to 1.3490,a price gap of 32 pips has therefore occurred,depending on your trade if your position is left open then you may have profited from the trade or lost as a result of this gap