dog day

noun

1

a

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

Word History

Etymology

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, in the meaning defined at sense 1a

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