folio

Origin

From Middle English folio (“leaf of a book”), borrowed from Medieval Latin foliō, Late Latin foliō, Latin foliō, the ablative singular form of Late Latin folium (“leaf or sheet of paper”), Latin folium (“leaf of a plant”), ultimately from Proto-Indo-European *bʰleh₃- (“bloom, flower”). Doublet of foil and folium, and distantly related to phyllo and phyllon. Senses 1, 2, 3.1, 5, and 6 relating to a leaf or page are derived from Medieval Latin foliō in references; sense 5 (“page in an account book”) may be derived from Italian foglio (“rectangular sheet of paper”), from Latin folium. Senses 3.2 and 3.3 relating to a paper size are from Italian in foglio or its etymon Latin in foliō.