noun
first year of high school; first-year high school student
Abbreviation of 高校一年(生). Used in school contexts to refer to the grade or the student.
彼は今年高一になった。
He became a first-year high school student this year.
高一の時、数学が苦手だった。
When I was in my first year of high school, I was bad at math.
Abbreviation of 高校一年(生).