The bid price as quoted by the market (exchange) is the price for that asset /option on asset, if any participant wants to buy. (‘Bid’ price of the exchange becomes the ‘ask’ price for the market participants)
The ask price as quoted by the market (exchange) is the price for that asset /option on asset, if any participant wants to sell. (‘Ask’ price of the exchange becomes the ‘bid’ price for the market participants)
The difference between the bid and the ask price is called the bid-ask spread.