In foreign exchange terminology, the Japanese Yen, or simply the Yen, refers to the currency of the country of Japan. The currency has the ISO 4217 code JPY, and it is most commonly-traded in the forex market as the counter-currency currency against the U.S. Dollar as the pair USD/JPY.
The Japanese Yen is one of the major currencies traded in the forex market. It usually trades against the U.S. Dollar in the forex market, but also trades actively against the E.U. Euro as the EUR/JPY currency pair.