Etymology
Learned borrowing from Latin bibliothēcārius (“librarian”), from bibliothēca (“library”) + -ārius, from Ancient Greek βῐβλῐοθήκη (bĭblĭothḗkē, “library”), from βῐβλῐ́ον (bĭblĭ́on) + θήκη (thḗkē). Compare French bibliothécaire and Italian and Spanish bibliotecario. By surface analysis, bibliotheca + -ary or bibliothec + -ary.