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

The Ultimate Dictionary Awaits

Expand your vocabulary and dive deeper into language with Merriam-Webster Unabridged.

1. Expanded definitions
2. Detailed etymologies
3. Advanced search tools
4. All ad-free

Discover what makes Merriam-Webster Unabridged the essential choice for true word lovers.

Start Your Free Trial Now