Order Book
The live list of all buy and sell orders at each price — the ledger of supply and demand on a trading venue.
An order book is the real-time record of outstanding buy orders (bids) and sell orders (asks) at every price level on an exchange. It’s the mechanism centralized exchanges use to match trades, in contrast to the pool-based pricing of AMMs.
The book reveals market structure: the spread between best bid and ask, the depth of orders (how much size the market can absorb), and clusters of orders that act as visible support or resistance. It’s also a stage for games — large fake orders (“spoofing“) and hidden orders distort what it appears to show, so reading it well means distrusting it a little.