school day

noun

any day on which school is conducted.
the daily hours during which school is conducted: The school day here is from nine to three.

Origin of school day

First recorded in 1580–90

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

I don't care if we do have to study for six hours every school-day.
Our Little Swiss Cousin
Mary Hazelton Wade
It was kind of you to write it, though it was your school-day.
Charlotte Bront
T. Wemyss Reid
But when you're sick on a school-day, you'll stay in bed till the next morning.
Penrod and Sam
Booth Tarkington
He spoke, for once, without due reflection, and with perhaps an exaggerated remembrance of your school-day offenses.
In the Midst of Alarms
Robert Barr
Joe and Mattie discuss these plans at the close of Joe's school-day, as they sit on his piazza, his flute for the time silent.
The Story of a Life
J. Breckenridge Ellis