Pip
The smallest standard price move in a forex pair.
For most pairs a pip is the fourth decimal place (0.0001); on yen pairs it is the second (0.01). Traders measure a stop or a target in pips, then multiply by the pip value and lot size to get the cash risk.
A pip is the standard unit of price movement in forex. For most pairs it is the fourth decimal place, 0.0001, so EUR/USD moving from 1.1000 to 1.1001 is one pip. On yen pairs, quoted to two decimals, a pip is 0.01. Many brokers also show a fifth decimal, a fractional pip or pipette, for finer pricing.
Pips are how traders size a trade. You measure the distance from entry to stop in pips, work out what one pip is worth for your lot size and pair, and multiply to get the cash you are risking. Get that arithmetic wrong and a position that felt small can risk far more than intended, which is exactly what a pip value calculator and a position size calculator are for.