CBOE: The Chicago Board Options Exchange; the first national exchange to trade listed stock options.

Change: The difference between the current price and the price of the previous day of a security.

Exchange: An area where an asset, option, future, stock or derivative is bought and sold.

Option: A contract that gives the owner the right, but not the obligation, to buy or sell a particular asset (the underlying stock) at a fixed price (the strike price) for a specific period of time (until expiration) . The contract also obligates the writer to meet the terms of delivery if the contract right is exercised by the owner.