Two-Way Quote
This type of quote provides more information to users than a last-trade quote, which quotes only the price at which the security last traded.
An example of a two-way quote would be: Citigroup quote of $52.50/$53.30.
This tells traders they can currently purchase Citigroup shares for $53.30 or sell them for $52.50. The spread between the bid and the ask is $0.80 ($53.30-$52.50).
Bid-Ask Spread
On an exchange, the difference between the highest price a buyer of a security or other asset is willing to pay and the lowest price a seller is willing to offer. Generally speaking, the more liquid an asset is, the lower the bid-ask spread is. As a result, currency, which is considered the most liquid asset, has an extremely low bid-ask spread.
Bid and ask
Bid and ask is better known as a quotation or quote.
Bid is the price a market maker or broker offers to pay for a security, and ask is the price at which a market maker or dealer offers to sell. The difference between the two prices is called the spread.