The time from when an option contract is created by a writer of that option to the expiration date; sometimes referred to as an option's 'lifetime.'
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.