The first day of the year in which the weather is nice enough for girls to wear shorts/skirts and show some skin; particularly celebrated on a college campus.
Meghan's cleavage had been hibernating for the winter. It was not until Boner Day that I got to see her voluminous rack.
by The Nightman April 16, 2009
1 more definition
The first warm day of the year, when women break out their summer outfits, and the streets are flooded with skin after a long, cold winter.
Hey...Tim...want to hit a patio? Today's Boner Day.
by Jer_TO May 06, 2013