day of days

Noun

 * 1)  A particularly noteworthy day; the day on which a milestone or especially memorable event occurs.
 * 2)  Sunday, especially Easter Sunday.
 * 1)  Sunday, especially Easter Sunday.
 * 1)  Sunday, especially Easter Sunday.
 * 1)  Sunday, especially Easter Sunday.
 * 1)  Sunday, especially Easter Sunday.

Usage notes

 * Used with more than random frequency to refer to major events in the sport of horse racing.

Synonyms

 * red-letter day