red letter day
Proposed by a contributor, not yet supported by evidence.
Sense 1
A special or memorable day
Examples
AI-drafted example auto-approved by rule (illustrative, not a corpus attestation)
Sources & notes
Listed in Wiktionary’s “English idioms” category (retrieved 2026-07-29); definition pending editorial review. Definition drafted by AI (@cf/meta/llama-3.3-70b-instruct-fp8-fast) and auto-approved by rule on 2026-07-31; pending editor spot-check.
Sense 2
A saint's day or holiday, marked in the calendars with red letters. Red letter men; Roman Catholics: from their observation of the saint days marked in red letters.
Ngày lễ hoặc ngày nghỉ được đánh dấu trên lịch
Machine-translated — suggest a fix
Era: ca. 1811 (Georgian)
Sources & notes
Historical definition reproduced from Grose’s Dictionary of the Vulgar Tongue (1811 edition, public domain; Project Gutenberg #5402, retrieved 2026-07-31). Reflects the attitudes of its era.
Common questions
What does “red letter day” mean?
A special or memorable day Literally: a day marked with red letters
Is “red letter day” formal or informal?
No register label has been reviewed yet — treat it as neutral and check the usage notes above.