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.

Options Clearing Corporation: A registered clearing agency whose shares are owned by the exchanges that trade listed equity options, OCC is an intermediary between option buyers and sellers. OCC issues and guarantees all listed option contracts.