A coin pair like BTC/USD represents the value of one cryptocurrency (BTC, or Bitcoin) compared to another asset, typically fiat currency like USD (U.S. Dollar). It shows how much of the quoted currency (USD) is needed to buy one unit of the base currency (BTC). Traders use coin pairs to speculate on price movements and exchange digital assets. The BTC pair is among the most popular and liquid in the crypto market. Understanding coin pairs is crucial for trading, as prices constantly fluctuate due to market supply and demand, global news, investor sentiment, and macroeconomic events.