zero period
n.— «The new schedule has seven 50-minute periods, and extends the school day by 15 minutes. Before, the high school day had six 55-minute periods, but many students took an extra class —- commonly called a “zero period”—before the regular day began.» —“High school reform arrives” by Carolyn Norton Herald-Sun (Durham, North Carolina) Aug. 23, 2006. (source: Double-Tongued Dictionary)
Further reading
Elena in Mt. Holly, North Carolina, wonders why beeline means “a direct route.” Well, once a bee has gathered sufficient nectar from flowers, she flies in a straight course back to the hive. In The Journal of Henry David Thoreau, 1837...
There are eight major planets, but more than a million minor ones, including asteroids. If you discover one, you get the honor of naming it. The Dictionary of Minor Planet Names includes minor planets named for rock bands, jazz musicians, poets, and...