A student in the third year of a school or program (e.g., third-year elementary/middle/high school or university student).
小学校の３年生は漢字をもっと習い始める。
Third-year elementary students begin to learn more kanji.
彼は大学の３年生で、来年就職活動をする予定だ。
He is a third-year university student and plans to look for a job next year.
今日、クラスの３年生が文化祭で発表した。
Today the third-year students from the class gave a presentation at the cultural festival.