Expiration
The date on which an options contract ceases to exist and the right to exercise expires.
Explanation
Options have various expiration cycles: weekly, monthly, quarterly, and LEAPS. Time decay (theta) accelerates as expiration approaches, especially in the final 30 days. After expiration, ITM options are automatically exercised and OTM options expire worthless.
Example
A March 17 expiration call must be exercised on or before March 17. After that date, the contract ceases to exist.