An order book is a list of buy and sell orders for a specific cryptocurrency.
The order book is a real-time, continuously updated list of buy and sell orders on a cryptocurrency exchange for a specific crypto pair, such as BTC/USD. The order book shows the quantity of the cryptocurrency to be bought or sold (the depth) and the price at which the trade is to be executed. It's divided into bid orders (buy orders) and ask orders (sell orders). The order book provides insights into the market depth, the supply and demand for the cryptocurrency, and potential resistance and support levels.
Some examples of how an Order Book can be used are these: