학창 시절이 · 학창 시절을
school days
Example
학창 시절에 가장 친했던 친구를 오랜만에 만났어요.
I met up with my best friend from school for the first time in ages.
Word parts
학 study+창 window+시 time+절 season
Literally 'study-window days' — the years spent learning by the classroom window.
Good to know
It covers all your school years together, and people usually say it looking back fondly.
Related words