Origin of Phrases - R
Red Letter Days
Meaning: A holiday, cause for celebration.
Example: When world hunger is solved it will be a red letter day.
Origin: Calendars typically have holidays marked in red ink. All other days are in black ink. Hence "red letter days" are cause for celebration. This saying, meaning holidays or festive days, comes from early prayer books and church almanacs. Religious holidays were printed in red ink to stand out from other events.