1Suffix attached to a number to indicate a student in the nth year of school — e.g., 一年生 (first-year student), 三年生 (third-year student). Used for elementary, middle, high school, and university grades.
妹は今年、小学一年生になりました。
My little sister became a first-grader this year.
息子は中学二年生で、来年受験です。
My son is in the second year of middle school, and next year he'll have entrance exams.
大学四年生になると、みんな就活で忙しくなる。
Once you become a fourth-year university student, everyone gets busy with job hunting.
高校三年生の夏休みは、ほとんど勉強で終わった。
My summer vacation as a third-year high school student was almost entirely spent studying.