What is Pip?
The smallest standardized price move on a forex pair — 0.0001 on most pairs, 0.01 on JPY pairs.
A pip ("percentage in point") is the smallest standardized price movement in forex pricing. On most pairs (EURUSD, GBPUSD) it is 0.0001 — the 4th decimal place. On Japanese yen pairs (USDJPY, EURJPY) it is 0.01 — the 2nd decimal. On gold (XAUUSD) conventions vary by broker, typically 0.10.
The pip VALUE — what one pip is worth in dollars — depends on lot size and the quote currency. For EURUSD: 1 standard lot = $10/pip, 1 mini lot = $1/pip, 1 micro lot = $0.10/pip. For USDJPY, you must convert ¥1000 back to USD using the current rate, so the pip value is roughly $6-9 per standard lot.
A "pipette" is 1/10th of a pip — the 5th decimal place — used by modern brokers for finer pricing precision (EURUSD = 1.08543 means three decimal digits past the pip).