red-letter

adjective

red-let·​ter ˈred-ˌle-tər 

: of special significance

Examples of red-letter in a Sentence

Recent Examples on the Web

The launch date of the iPhone 18 Pro remains a red-letter day for the industry. — Ewan Spence, Forbes.com, 22 Aug. 2026

These days, most red-letter sins in NCAA sports come in gray, and more often invisible ink. — Fort Worth Star-Telegram, 8 June 2026

These felt like big, kind of red-letter games. — Bob Goldsborough, Chicago Tribune, 15 Apr. 2026

Wembanyama’s injury marred what was otherwise a red-letter day for the Spurs, who cemented the franchise’s eighth 60-win season one year after posting a 34-win campaign. — Jeff McDonald, San Antonio Express-News, 7 Apr. 2026

Word History

Etymology

from the practice of marking holy days in red letters in church calendars

First Known Use

1704, in the meaning defined above

Rhymes for red-letter

• abettor
• newsletter
• typesetter
• better
• bettor
• debtor
• fetter
• getter
• letter
• netter
• petter
• rhetor

Kids Definition

red-letter

adjective

red-let·​ter

ˌred-ˌlet-ər

: worth remembering especially in a happy or joyful way

a red-letter day

Etymology

from the practice of marking holy days in red letters in church calendars