# red letter day

idiom

Source: https://englishreference.com/idiom/red-letter-day
Updated: 2026-08-10

## Meaning

A particularly significant day; a day of personal or sectarian celebration.

## Examples

- Today is a red letter day for our family.
- Graduating from university after years of hard work was truly a red letter day for her.
- The signing of the peace treaty marked a red letter day in the nation's history, signaling the end of decades of conflict.

## Origin

The expression alludes to a practice dating to classical antiquity, wherein important dates were marked in red ink on calendars. It remains a surviving trace of the ecclesiastical and civil custom of distinguishing festivals and saints' days from the black-inked mundane.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.