Pip value is how much a one-pip price move is worth in your account currency. It depends on the currency pair, the lot size traded, and — for cross pairs — the current exchange rate. Because pip value scales directly with position size, it's the number that turns a price movement in pips into an actual profit or loss figure.
Example
One standard lot (100,000 units) of EUR/USD has a pip value of roughly $10; the same pip on a 0.1 mini lot is worth about $1.