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

Just keep in mind that the tired brain is not you on a good day.

From BBC • Jun. 13, 2026

Racing Bulls had a good day with Arvid Lindblad taking the best result of his rookie season with sixth place behind team-mate Liam Lawson.

From BBC • Jun. 7, 2026

If people happily complain about waking up the next day with sore feet, then it was a good day.

From Salon • Jun. 6, 2026

“On a good day, I’m a 7-3. I beat my own record by three-fourths of an inch. Even at 6-8, I was way over it.”

From Los Angeles Times • May 17, 2026

“Rather mixed, Madam. She has one good day, and then a bad. She’s not too bad in herself, you know. She will be pleased to see you I’m sure.”

From "Rebecca" by Daphne du Maurier