The Sirius star
The name comes from the Sirius star, which is the brightest star in the night sky. Sirius actually comprises two stars, Sirius A and Sirius B, that circle around each other. The easiest way to find Sirius on the Northern Hemisphere is in winter when it is high above the horizon. Simply draw a straight line to the left of Orion's belt. The line will point to Sirius, which is roughly 8-times as far as the belt is long.
Interestingly, Sirius can be found in various colour shades, which depends on the angle of the light coming through the Earth’s atmosphere.
In ancient Egypt, Sirius had a significant symbolic and religious meaning as his appearance on the horizon, just before sunrise, announced the annual flooding of the Nile. After 70 days, when reappearing again, it introduced the period of prosperity as well as a period of hard work.
The star is also known as the “Dog Star”, since it’s a part of the Canis Major (Greater Dog) constellation. Thanks to Sirius, we also talk about the “dog days” when we refer to an unpleasantly hot period of summer. So, it was actually Sirius who gave the name to the concept, and not dogs, although dogs find “dog days” unpleasant as well.