The G10 (Group of Ten) refers to the ten major industrialized nations that agreed to the General Arrangements to Borrow with the IMF. In forex, the G10 currencies (USD, EUR, JPY, GBP, CHF, CAD, AUD, NZD, NOK, SEK) are the most liquid and widely traded.
Example
“A forex trader focused on G10 pairs like EUR/USD and USD/JPY because they offered tighter spreads and deeper liquidity than exotic currency pairs.”