noun
quire; gathering; section; signature
Technical term in bookbinding for a set of folded sheets that form a section of a book.
製本では、折丁を重ねて綴じていきます。
In bookbinding, quires are stacked and bound together.
Compound of 折り (ori, 'folding') and 丁 (chō, 'leaf' or 'sheet'), referring to folded sheets in bookbinding.