Found 2 items, similar to red-letter day.
English → English (WordNet) Definition: red-letter day red-letter day n : a memorably happy or noteworthy day
English → English (gcide) Definition: Red-letter day Red-letter \Red"-let`ter\ (-l?t`t?r), a. Of or pertaining to a red letter; marked by red letters. [1913 Webster] Red-letter day, a day that is fortunate or auspicious; -- so called in allusion to the custom of marking holy days, or saints' days, in the old calendars with red letters. [1913 Webster]