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出典:Wiktionary
出典:『Wiktionary』 (2010/07/27 08:08 UTC 版)
From the practice of marking feast-days in red on church calendars.
red-letter day
出典:『Wiktionary』 (2026/03/21 22:08 UTC 版)
An allusion to the practice, dating to classical antiquity, of marking important days in red on calendars.
red letter day (plural red letter days)
Red-Letter Day