A period of from four to six weeks, in the summer, variously placed by almanac makers between the early part of July and the early part of September; canicular days; -- so called in reference to the rising in ancient times of the Dog Star (Sirius) with the sun. Popularly, the sultry, close part of the summer; metaphorically, a period of inactivity.
the hot period between early July and early September; a period of inactivity
The hot, sultry period between early July and mid-August, so called because Sirius, the Dog Star (the brightest star of the night sky), rises and sets with the Sun during this time. Ancient Egyptians believed the heat of this brilliant star added to the Sunâ€™s heat to create the hot weather.