noun
third grade; third grader
Abbreviation of 小学校三年(生). Used in school contexts to refer to the third year of elementary school or a student in that year.
うちの子は今年小三です。
My child is in third grade this year.
小三の担任の先生はとても優しい。
The third-grade homeroom teacher is very kind.
Full formal term; 小三 is the common abbreviation.
Abbreviation of 小学校三年(生).