noun
librarian; person in charge of a library
Often used in school contexts for the student or staff member responsible for the library.
彼女は学校の図書係です。
She is the school librarian.
図書係の仕事は本の貸し出しと整理です。
The librarian's job is lending out and organizing books.
Compound of 図書 (books) and 係 (person in charge).