-A list of prices (generally bid, ask, and last) for stock at a particular point during the trading day. Stocks were previously quoted in fractions, but now nearly all exchanges use decimals. Stock quotes are either in real-time or 15 minute delay.

Bid

-The price a buyer is willing to pay for a security. This is one part of the bid with the other being the bid size, which details the amount of shares the investor is willing to purchase at the bid price. The opposite of the bid is the ask price, which is the price a seller is looking to get for his or her shares.  

-The use of bid and ask is a fundamental part of the market system, as it details the exact amount that you could buy or sell at any point in time. Remember that the current price is not the price for which you can purchase the security, but the price at which the shares last traded hands. If you want to get an idea of the price for which you can buy a security, you need to look at the bid and ask prices because they will often differ from the current price.

-An offer made by an investor, a trader or a dealer to buy a security. The bid will stipulate both the price at which the buyer is willing to purchase the security and the quantity to be purchased.

-The price at which a market maker is willing to buy a security. The market maker will also display an ask price, or the amount and price at which it is willing to sell.  

This is the opposite of the ask, which stipulates the price a seller is willing to accept for a security and the quantity of the security to be sold at that price.

-An example of a bid in the market would be $23.53 x 1,000, which means that an investor is willing to purchase 1,000 shares at the price of $23.53. If a seller in the market is willing to sell that amount for that price, then the transaction is completed.

-Market makers are vital to the efficiency and liquidity of the marketplace. By quoting both bid and ask prices on the market, they always allow investors to buy or sell a security if they need to.

Ask

-The price a seller is willing to accept for a security, also known as the offer price. Along with the price, the ask quote will generally also stipulate the amount of the security willing to be sold at that price.

Sometimes called "the ask".  

-This is the opposite of bid, which is the price a buyer is willing to pay for a security, and the ask will always be higher than the bid. The terms "bid" and "ask" are used in nearly every financial market in the world covering stocks, bonds, currency and derivatives. An example of an ask in the stock market would be $5.24 x 1,000 which means that someone is offering to sell 1,000 shares for $5.24.

Quotation

-A very common term which actually refers to two numbers - the highest bid price currently available for a security or commodity, and the lowest ask price currently available for the same security/commodity.  

A security's or commodity's quotation represents two pieces of information: the price an investor would need to pay to purchase an asset at a particular moment in time (the lowest price "asked" by sellers) and the price an investor would receive for the same asset if they sold it at the same time (the highest "bid" by potential buyers). Taken together, the difference between the two represents the liquidity cost an investor incurs when trading an asset, since they must buy at the bid price and sell at the ask price.