Date Certain A term identifying the date on/by which the specified actions of a contract can be reasonably completed. This date is important, as it is generally considered legally binding. Investopedia Says: The third Friday of each month is an example of a date certain for option expiry. Remember, options (and in fact all derivatives) are simply contracts between two parties. Related Terms: Derivatives Expiration Date Option Settlement Date Sum Certain Triple Witching Hour |