Definition of dog day
1a dog days plural : the period between early July and early September when the hot sultry weather of summer usually occurs b : a day in dog days : a hot sultry day
2 dog days plural : a period marked by dull lack of progress the dog days following any major upheaval
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Origin and Etymology of dog day
back-formation from dog days, translation of Late Latin dies caniculares, translation of Greek hēmerai kynades; from their being reckoned in ancient times from the heliacal rising of the Dog Star (Sirius)
First Known Use: 1538
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