noun
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)
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