means A person trained to organize, preserve, and help people find information and books in a library.

from From the Latin librarius, meaning 'of books,' which itself grows from liber, 'book' — though liber first meant the inner bark of a tree, the very stuff people wrote on before paper. So buried in the word is a memory of scraping words onto bark. The '-an' ending arrived later to name the keeper of all those barks-turned-books, settling into English by the 1700s in roughly its modern sense.