Units of paper quantity and US measure, in some sources, a quire was originally 24 sheets.) Quires of 15, 18 or 20 sheets have also been used, depending on the type of paper. The current word "quire" derives from OE "quair" or "guaer", from OF "quayer", "cayer", (cf. modern Fr. "cahier"), from L. "quaternum", "by fours", "fourfold". Later, when bookmaking switched to using paper and it became possible to easily stitch 5 to 7 sheets at a time, the association of "quaire" with "four" was quickly lost. In the Middle Ages, a quire (also called a "gathering") was most often formed of 4 folded
Paper size containing less than 10 micrometers of paper The international paper size standard is ISO 216. It is based on the German DIN 476 standard for paper sizes. ISO paper sizes are all based on a single aspect ratio of the square root of 2, or approximately 1:1.4142. There are different series, as well as several extensions. The following international paper sizes are included in Cascading Style Sheets (CSS): "A3", "A4", "A5", "B4", "B5". The base A0 size of paper is defined as having an area of 1 m and a dimension ratio of 1 to , making the A0 paper