librarial UK /laɪˈbɹɛəɹi.əl/US /laɪˈbɹɛɹi.əl/ adjective1 •(rare) Of, pertaining to, or characteristic of a library, librarianship or librarians.Those wire-framed glasses made Babel look like a librarian, but his silence is not librarial. — 1986 formsmore librarial · most librarial