Cover: To close out an open position - to buy back as a closing transaction an option that was initially written. This term is used to describe the purchase of an option or stock to close out an existing short position for either a profit or loss.

Covered: A written option is considered to be covered if the writer also has an opposing market position on a share-for-share basis in the underlying security. That is, a short call is covered if the underlying stock is owned, and a short put is covered (for margin purposes) if the underlying stock is also short in the account. In addition, a short call is covered if the account is also long another call on the same security, with a striking price equal to or less than the striking price of the short call. A short put is covered if there is also a long put in the account with a striking price equal to or greater than the striking price of the short put.

Covered Option: An open short option position that is fully offset by a corresponding stock or option position. That is, a covered call could be offset by long stock or a long call, while a covered put could be offset by a long put or a short stock position. This insures that if the owner of the option exercises, the writer of the option will not have a problem fulfilling the delivery requirements.

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.

Naked Uncovered option: A short option position that is not fully collateralized if notification of assignment is received. A short call position is uncovered if the writer does not have a long stock or long call position. A short put position is uncovered if the writer is not short stock or long another put.