"sheet of paper, one side of a printed or written leaf of a book or pamphlet," 1580s, from Middle French page, from Old French pagene "page, text" (12c.), from Latin pagina "page, leaf of paper, strip of papyrus fastened to others," related to pagella "small page," from pangere "to fasten," from PIE root *pag- "to fasten."
Earlier pagine (c. 1200), directly from Old French or Latin. The word is usually said to be from the notion of individual sheets of paper "fastened" into a book. Ayto and Watkins offer an alternative theory: vines fastened by stakes and formed into a trellis, which led to sense of "columns of writing on a scroll." When books replaced scrolls, the word continued to be used. Related: Paginal.
Page-turner "book that one can't put down" is from 1974; earlier (by 1959) an apparatus or person who turns the pages of an open book, as for a performing musician.