Books made by printing two pages of text on each side of a sheet of paper, which is then folded once to form two leaves or four pages, are referred to as folios (from Latin, foliō, ablative of folium, leaf[1]). Those made by printing four text pages on each side of a sheet of paper and folding the paper twice to form a gathering containing four leaves or eight pages are called quartos (fourths). Similarly, books made by printing eight pages of text on each side of a sheet, which was then folded three times to form gatherings of eight leaves or sixteen pages each, are called octavos.