red-letter day

British  

noun

1. a memorably important or happy occasion

---

red-letter day Cultural  

1. A special or memorable day; the expression refers to the old custom of printing holidays in red on calendars: “John got promoted and engaged to be married yesterday; it was truly a red-letter day for him.”

---

red-letter day Idioms  

1. A special occasion, as in When Jack comes home from his tour of duty, that'll be a red-letter day. This term alludes to the practice of marking feast days and other holy days in red on church calendars, dating from the 1400s. [c. 1700]

---

Etymology

Origin of red-letter day

C18: from the red letters used in ecclesiastical calendars to indicate saints' days and feasts

Example Sentences

This was a red-letter day for Adelaide-born Head as he scored a stunning century in front of a packed crowd on familiar territory.

From BBC • Dec. 7, 2024

Saturday was a red-letter day for the history of art in Southern California.

From Los Angeles Times • Jun. 21, 2022

“The eventual purchaser will be able to steward them into publication, which will be a red-letter day for Brontë scholarship,” he said.

From Seattle Times • Mar. 30, 2022

Berger’s meeting with his idol remains a red-letter day in his life.

From Washington Post • Feb. 11, 2021

It was a red-letter day for Elizebeth, proof that she had lived up to her old dreams of achievement.

From "The Woman All Spies Fear" by Amy Butler Greenfield