Bid Price: The bid price is the price a buyer is willing to pay for a particular asset. The term "bid" can be used interchangeably with buy. "Best bid" is the highest price, at the top of the orderbook.
Ask Price: The ask price, also known as the "offer" or "asking price," is the lowest price at which a seller is willing to sell their asset The term "ask" can be used interchangeably with the term sell. "Best ask" is the lowest price, at the bottom of the orderbook.
Mid Price: The mid-price is the average between the current bid and ask prices.