good day

American  

interjection

1. a conventional expression used at meeting or parting during the daytime.

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good day British  

1. a conventional expression of greeting or farewell used during the day

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good day Idioms  

1. Also,. Formal ways of saying “Hello” or “Goodbye.” For example, He began rather oddly by addressing the audience with “Good day,” or “Good afternoon, ladies,” said the sales clerk as we walked out. All these greetings represent an abbreviation of the now obsolete God give you a good day (afternoon, etc.), which dates from about 1200. Also see good night.

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Etymology

Origin of good day

Middle English word dating back to 1175–1225

Example Sentences

On a good day, she sees half of her old business; on a bad day, a fifth.

From The Wall Street Journal • Mar. 25, 2026

Witching or not, Friday hasn’t been a good day for the stock market in recent weeks.

From Barron's • Mar. 20, 2026

It’s never a good day to be fired, but Noem’s departure comes at a particularly unfortunate moment for her.

From Slate • Mar. 5, 2026

"Yesterday was such a good day for him," Thelma told Jamaica's Gleaner newspaper.

From BBC • Jan. 26, 2026

It might be a good day to be out of Moscow.

From "Fallout: Spies, Superbombs, and the Ultimate Cold War Showdown" by Steve Sheinkin