school bag; schoolbag
Typically a handheld or shoulder-hung bag used by students to carry books and supplies.
I got a new school bag.
He headed to school with his school bag slung over his shoulder.
Also means 'school bag' but is less common and may sound slightly more formal or descriptive.
Compound of 学生 (student) and 鞄 (bag). The exact historical derivation is straightforward; the word is a modern compound.