Super Saturday

Proper noun

 * 1)  The last Saturday before Christmas, a major day of revenue for retailers.
 * 2)  A Saturday on which a large number of U.S. states hold caucuses (elections) for the process of nominating presidential candidates.
 * 1)  A Saturday on which a large number of U.S. states hold caucuses (elections) for the process of nominating presidential candidates.

Usage notes
If Christmas Eve falls on a Saturday, Super Saturday can occur as the last Saturday prior to Christmas Eve, being Saturday, December 17.