A hedge is any position designed to offset the risk of another. In forex, common hedging patterns include: opening a short EUR/USD against a long EUR/GBP to isolate the GBP leg, buying gold (XAU/USD) against a long USD position to hedge dollar weakness, or simply closing a portion of a winning position to "bank" partial profit.
US-regulated brokers (CFTC) prohibit traditional same-pair hedging under the FIFO rule, which forces traders to close existing positions before opening opposite ones. Offshore and non-US brokers allow direct hedging, which is one reason many multi-leg strategies require a non-US broker.