academic year; school year
Refers to the year-long period of schooling, often starting in April in Japan.
日本の学年は4月に始まります。
The school year in Japan starts in April.
year in school; grade in school
Indicates a student's current year level, e.g., 1st grade, 2nd grade.
彼は学年で一番成績がいい。
He has the best grades in his year.
When April comes, students move up to the next grade.
She became the top student in her grade.
He's in a different grade from me, so I haven't talked to him much.
The students were seated in groups divided by grade level.
学年 refers to a grade level or cohort of students in school, whereas 年度 refers to the twelve-month administrative period itself.
same school year; same grade
school year calendar; academic calendar