The period of one's life when one attends school(noun)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "schooldays" in a sentence
"That said, I might try it with the next group of businesspeople I get, just to see if they recall their schooldays"
"'To say that I was never the belle of the ball in my schooldays is the understatement of the century, but here ... can you imagine it, Storm, me actually outshining Barbara Benton and Helen Worthington both at once?'"
"This is one of the expeditions I have looked forward to all my life, ever since I read "The Lady of the Lake" in schooldays."