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
Jameela in Charlotte, North Carolina, says her family refers to their television’s remote control as the clicker, but her friends insist on calling it the remote. These devices go by other names as well, including doofer, flicker, zapper, and...
Amid court-ordered busing in the 1970s, a middle-school teacher tried to distract her nervous students on the first day of class with this strange assignment: find a monarch caterpillar. The result? A memorable lesson in the miracle of metamorphosis...