[ShabbosGoy]

Bid is latest buy order. Ask/Offer is latest sell order.

Many exchanges have the “maker-taker” model. If you add liquidity to the order book, you are paid by the Exchange. If you take liquidity away from the order book, you pay the Exchange.

[Veratyr]

It's not the latest order, it's the highest (bid)/lowest (ask) _open_ order.

[bob_theslob646]

What the market is quoted at , is the latest buy or sell order.

The price you can buy at is the ask, the price you can sell at is the bid.