A pip is the unit you count profit or loss in. Most currency pairs, except Japanese yen pairs, are quoted to four decimal places. The fourth spot after the decimal point (at one 100th of a cent) is typically what one watches to count "pips". Every point that place in the quote moves is 1 pip of movement. For example, if the GBP/USD rises from 1.5863 to 1.5864, the GBP/USD has risen 1 pip.