A stream of market information (prices, volumes, quotes) delivered to trading systems. A data feed provides the latest bid/ask prices and transaction data so traders (or algorithms) can decide when to buy or sell. Raw feeds may come directly from exchanges or brokers; normalized feeds come from data vendors. In practice, a “market data feed provides price and other information so market participants can decide whether to buy or sell”. Forex robots ingest these feeds (often via API) to get live price updates.