Groundhog Day[groundˈhôgˌ, -hŏgˌ]
A groundhog looks out of his hole on Groundhog Day.
Groundhog Day definition by Webster's New World
Groundhog Day definition by American Heritage Dictionary
Groundhog Day - Cultural Definition
February 2. According to the legend of Groundhog Day, if a groundhog (a woodchuck) comes out of his hole on that day and sees his shadow, six more weeks of winter will follow. If no shadow appears, there will be an early spring.