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]